The best part is the "real" history of what happend between Way Jin and Jin Way. Personally I loved the giant panda.
And how Aang later reveals the story to be a hoax.
The time when Zuko lands on the Southern Pole village and a boomerang hits him on the back of his head.
And did anyone realize that Iroh slept through that whole episode of capturing the Avatar?
Which is made only funnier upon remembering that Zuko told someone "Wake my uncle!" right before they went to the village.
From "The Northern Air Temple"
Katara: Do you really think we'll find Airbenders at the Northern Air Temple? Sokka: Do you want me to be like you or totally honest? Katara: Are you saying I'm a liar? Sokka: I'm just saying you're an optimist. Same thing, basically.
"Don't worry, Sokka. Where we're going, you won't need pants!" 
From that same episode, I believe, Aang is enjoying the fame he's getting from the young female population of the island, to the point of it going overboard several times. One event: A painter trying to capture an image of just him and one girl. Every time he looks back up, there are MORE girls in the picture, until they overshadow Aang. Cut back to the painter with a...not very amused look on his face.
Again from "The Warriors of Kyoshi": Zuko abandons his dinner to set the course to Kyoshi. Of course, Iroh asks Zuko if he was going to eat his meal, only for Zuko to turn around and grab his plate, declaring, "I WAS GOING TO SAVE IT FOR LATER!", much to Iroh's disappointment.
Iroh: Prince Zuko, you're really going to get a kick out of this... the Lotus Tile was in my sleeve the whole time!"
Guess what? Zuko didn't get a kick out of it. In fact, he takes the tile and flings it into the river.
From the same episode, Zuko pointing and laughing like a dorky ten-year-old when the pirate freaks out over the loss of his boat. Considering he'd been acting like a slightly more agreeable Vegeta up until this point, it was hilarious to see him act so childish and petty.
This is actually the only time in the entire series that Zuko laughs out loud. Ever.
And then the pirates steal HIS boat.
Zuko: HAHAHAHA-HEY!! That's MY boat!!
For some reason this one always cracks me up--
Iroh: Can you believe it ? Not a single lotus tile in the entire marketplace! Zuko: It's good to know this trip was a complete waste of time FOR EVERYONE!
From that same episode, this dialogue shortly after the Gaang gets captured:
Katara: Aang, this is all my fault. Aang: No, Katara, it isn't. Iroh: (to Katara) Yeah, it kind of is.
In somewhat of the same vein, from the episode Winter Solstice Part One: The Spirit World:
Katara: (to Aang, about stopping Hei Bai) I believe in you. Sokka: (Encouraging tone) Yeah... We're all gonna get eaten by a spirit monster.
Also from the "Water Scroll" episode:
Iroh: Are you two so busy fighting that you cannot see your own ship has set sail? Zuko: We have no time for your proverbs, Uncle! Iroh: (pointing at the pirates' ship)It's no proverb! ! (Zuko bursts out laughing, until he notices his ship has been stolen by the pirates) Zuko: HEY! That's my boat! Iroh: Maybe it should be a proverb...
The fact that Iroh breaks up the fight by grabbing Zuko's ponytail.
Iroh making the toothy monkey face.
While Iroh tells Zuko that he changed their ship's course so Iroh could go shopping for another Lotus Tile, the prince just stands there fuming. At the end of Iroh's explanation, he looks up and breathes fire. As smoke begins to fill the room, Iroh cheerfully remarks, "I'm lucky to have such an understanding nephew."
The scene in Imprisoned where Katara and Sokka use bad acting to convince the Fire Nation guards that Katara is an earthbender:
Katara: You heard me! A giant-eared cretin! Do animals use them for shade? I bet elephants gather around and make fun of how large your ears are!
And the Fire Nation soldier just looks a bit embarrassed for his mistake.
Also from Imprisoned:
Warden: Well, which was it, a buffalo or a bison? Guard 1: Uh, I'm not sure what the difference is, but that's not really the point, is it, sir? Warden: I'll decide what the point is, fool! (throws guard overboard, turns to second guard) You! Wake up the captain! Search the entire rig! Guard 2: Sir... that was the captain you just threw overboard. Warden: Then wake up someone I haven't thrown overboard and search this rig! There's something going on here and I don't like it!
That scene was made 10 times more funny by the casting of George Takei as the Warden.
The entirety of "The King of Omashu", but highlights include:
Aang's ridiculously long pseudonym, which Katara is amazingly proficient at ad-libbing and Bumi somehow remembers perfectly.
Lettuce leaf. Kangaroo Island. "No Firebenders here!" "Take them to the chamber that was once bad!" (And newly refurbished.) "My cabbages!" Momo being too fat to get out the air duct.
Anything and everything Bumi says during the challenges, but especially his comments during his duel with Aang. "It's getting a mite drafty in here. Did someone leave a window open? Were you hoping I'd catch cold?"
Sokka's theory on Bumi's name, and Katara's response: "We're gonna keep trying, but that is a good backup." Also, when asked how she's doing: "Other than the crystal slowly encasing my entire body, doing great!"
This, from "The Storm":
Sokka: "I'm too young to die!" Old Fisherman: "I'm not, but I still don't wanna!"
Sokka: "You guys wanna hear about my dream? (Katara gives him a look) That's okay. I don't wanna talk about it anyway."
Sokka: "This was in my dream! We shouldn't go to the market today." Katara: "Why, what happens in your dream?" Sokka: "Food eats people! (beat) Also, Momo could talk. You said some very unkind things."
At the very beginning of that episode, Aang wakes up everyone, and Sokka sits up, half-awake, knife and boomerang in hand, and says in a very sleepy voice: "What happened? Did we get captured again?"
And the look on Iroh's face as he's giving Lieutenant Jee the "Don't bring that topic up if you know what's good for you" sign. It doesn't work, but if you look in the background, it makes you die laughing.
There was another episode where Iroh buys a little monkey idol with ruby-encrested eyes, and makes the same goofy grinning expression it does.
With Katara and Sokka both sick after being caught in a storm, the first time Momo tries to fulfill Katara's request for water, he comes back with a mouse. A little later, we cut back to them and find that Momo still hasn't gotten the idea, and in the meantime has filled the cave with a mountain of odds and ends. The latest is a crown he puts right on Katara's head (Funny Moment of Crowning?), causing the hallucinating Sokka to call her "your majesty."
Zuko: For the last time, I'm not playing the tsungi horn.
In "Winter Solstice Part 1," Zuko comes across Iroh lounging in a hot tub, and angrily demands that his uncle hurry up and get ready for the pursuit. Iroh doesn't want to leave right away, but at Zuko's insistence, he stands up. Did we mention that the hot tub is only about thigh height?
Zuko: (waves his arms frantically in front of his face) No, it can wait!
Also sets up a nice Chekhov's Gag after Zuko and Iroh have beaten down the earthbenders who'd captured the latter:
Aang: Two? Katara: He tried to get the first fishhook out with another fishhook.
When Zhao starts up one of his hammiest moments in the series after capturing the Moon spirit:
Zhao: "They will call me Zhao the Conqueror! Zhao the Moonslayer! Zhao the INVINCIBLE!(Momo jumps on his head) Get it off! GET IT OFF!"
Zuko splashing hot tea on his face in "Bato of the Water Tribe."
Same episode, the very end of it.
Zuko: Uncle? I don't remember you getting hit with the tongue. Iroh:Shhh...
Which is then topped off by Jun's absolutely outragedexpression (she's frozen in position directly on top of him). Being completely justified in doing so only makes it funnier.
Iroh is a goldmine, in that same episode there's a momentary break in the epic fight scene to him testing out the nuns' perfumes, looking side to side suspiciously and then slipping it up his sleeve with a ^_^ expression.
From The Blue Spirit, as Aang is chained up, the frozen frogs he has been gathering begin thawing and hopping away.
"No, frogs! Come back, and stop thawing out! My friends need to suck on you!"
Zhao coming to find Aang gone, and the lone, defrosting frog crawling away.
The Blue Spirit not even hesitating a beat between Zhao declaring "the Avatar must be taken alive" and putting his swords to Aang's throat, after their awesome teamwork.
Zhao's interrogation of the guards in "The Deserter".
Local Commander "...but other than that, the festival went off without a hitch!" flaming debris hits directly behind them, and the little group all get 'We're screwed' expressions Local Commander (weakly) "No fights, theft was way down...." Zhao "I DON'T CARE ABOUT YOUR LOCAL CRIME RATES!"
After Aang gets free and starts looking for his glider, he peeks into a couple rooms without much success. He opens the door on a third room to find Iroh, snoozing away. He quietly shuts the door, whispering "sorry..."
Aang: *while Koh has his back to him, while realizing that he's already seen the Ocean and Moon spirits* "The Koyfish!" Koh: *whips around* Aang: *epic poker face* "I must be going now."
"Can your science explain why it rains?"
"Yes! Yes it can!"
This exchange from the end of "The Fortune Teller:"
Sokka: "No offense, but I hope you've all learned a little lesson about not relying on fortunetelling too much." Villager: "Ah, but Aunt Wu predicted the village would not be destroyed, and it wasn't! She was right after all!" Sokka:"I hate you!"
The Pollyanna: Iroh doesn't seem remotely worried even in the most life threatening situations, like in this fantastic monologue of his, while enjoying a massage...
"Who knew that floating on a piece of drift wood for three weeks with no food or water, and sea vultures waiting to pluck out your liver could make one so tense?"
And all that Zuko is bothered about is that he's been banished for three years to the day.
From "The Cave of Two Lovers":
After a cave-in in the titular cave.
Nomad: "It's no use; we're separated. But at least you have us!" Sokka: "NNNNAAAAAAHHHHHHH!!!!"
Meanwhile, in the B-plot.
Zuko: "If the Earth Kingdom finds us, they'll have us killed! Iroh: "But if the Fire Nation finds us, they'll hand us over to Azula." Zuko: *beat* "Earth Kingdom it is."
Hell, half of that episode counts—between Iroh's White Jade plant escapade and 90% of Sokka and near-on everything that any of the nomads says...
Iroh's absolutely causal and unconcerned about the fact that he's just poisoned himself and when the rashes reach his throat, he will stop breathing. He's only cheerful about the fact that he's found the antidote, but then he thinks that it may be another species that causes blindless...
And look at the shock on Zuko's face...you can't tell if he's more worried about his uncle's condition or rendered speechless by Iroh's attitude.
And we can't forget just before the White Jade plant's effects on Iroh is revealed, Zuko comes back from fishing with a -huge- spear, and nothing to show for it but the -tiniest- little fish wriggling on the end of it.
And I'm partial to Aang's dreamy "Us...kissing..." and the ensuing discussion.
"If it was a choice between kissing you and dying...."
"Don't let the falling rocks turn your smile into a frown!"
The Gilligan Cut for when the group tries flying instead of using the secret cave tunnel.
Sokka: <singed and deadpan> "Secret Love Cave, let's go."
We had this gem when the persuing Fire Nation soldiers refused to enter the cave. They apparently sing hippie love songs during music night.
Soldier: It's too dangerous! Haven't you heard the song?
Sokka and the nomads charming the badger moles with music.
After they get out of the tunnel:
Sokka: How did you guys get out? Aang: Just like the legend says. We let love lead our way! Sokka: Really? We let huge, ferocious beasts lead our way.
Also, Zuko and Iroh at the Earth Kingdom hospital place thingy, where they meet Song and come up with their fake names.
Zuko: Names? Of course we have names! Uh... I'm... Lee, and this is my uncle, uh... Mushi. Iroh glares at him Iroh: Yes, my nephew was named after his father, so we just call him Junior. Zuko is furious and gives the Off with Your Head Gesture
The "secret tunnel" song.
Nomad: Uh... I forgot the next line, but then it goes: SECRET TUNNEL!!!!! Secret Tunnel!!!
Chong figures out something very important.
Chong: Nobody react to what I'm about to tell you... but I think that kid might be the Avatar. Sokka: (Face Palm)
From "The Blind Bandit":
The Boulder: The Boulder feels conflicted about fighting a young, blind girl. Toph: Sounds to me like you're scared, Boulder! The Boulder: (beat) The Boulder is over his conflicted feelings and is now ready to bury you in a ROCK-ALANCHE! Toph: Whenever you're ready, The Pebble! *mischievous laugh*
Made even more awesome because Boulder's voice actor, Mick Foley, was hamming it up, channeling the spirit of The Rock, and The Boulder's facial expression when Toph says he's scared.
Toph using earthbending under one of the The Boulder's feet to split his legs and the Boulder's painful reaction. As well as when she uses earthbending again to send the Boulder slamming into the side of the stadium.
How could we forget Sokka's line here?
Katara (about Toph): She's not really blind. It's just part of her character right? Aang: I think she is. Sokka: I think she is....GOING DOWN!
When Sokka whispers "water tribe".
When Sokka gives Toph her championship belt back, he tosses it to her (it takes the Gaang until somewhere in season 3 to consistently remember she's blind). The belt whacks her right on the head.
Sokka: This (points to his hair) is a warrior's wolf-tail! Katara: Well, it certainly tells the other warriors that you're fun and perky!
Same episode. When given the choice between capturing the Avatar or attacking her brother, Azula's first move in the fight is to attack Zuko.
During the fight, Azula almost falls down a gaping hole in a building, but regains her balance at the last second. Then Zuko rushes in, screaming in a Hot-Blooded manner, right into the hole. Aang's "Ooo, that had to hurt!" expression watching this is priceless.
And Toph and Iroh's little tea party. It was heartwarming and cute, but also the entire situation was pretty hilarious.
Iroh: You seem a little too young to be travelling alone. Toph: You seem a little too old.
And Toph's completely cranky and tired expression, contrasting with Iroh's merry demeanor.
"THIS IS MY CALM FACE!"
Azula's plan to get Ty Lee to come with her.
Azula: What kind of dangerous animals do you have?... Release them all!
Sokka pulling a bubble pipe out of Hammerspace and Katara asking "Where'd you get that?"
Sokka's detective outfit that episode was TV Tropes Made of Win Archive. Not only the pipe, but a hat with a little set of magnifying glasses on a track around the brim! He's a freaking contextually-consistent Sherlock Holmes parody. And guess what? That hat is based on a real kind of Korean hat. There is a real hat that looks like that hat.
Sokka is stuck neck deep in a crack while a baby moose-lion looks on (long story) and after making friends with it, it brings (the very hungry) Sokka an apple. Sokka struggles with his neck and hands and manages to toss his boomerang out next to the apple. What sells it is his reaction:
"Haha, rock beats airbender!" from the same episode. Sokka looks like an overgrown caterpillar when he says it.
The exchange that followed later on in this episode, where Sokka eventually grew so desperate for rescue that he was ready to renounce carnivorism. Nevertheless, he is rescued immediately after;
Actually everything Sokka does and says is hilarious in that episode.
Sokka: Okay Karma person or thing whoevers in charge of this stuff, if I can just get out of this situation alive, I will give up meat, and sarcasm. Ok? That's all I got. It's pretty much my whole identity, Sokka, the meat and sarcasm guy, but I'm willing to be Sokka the veggies and straight talk fellow. Deal? (Aang appears) Sokka: Aang! Thank goodness! Have you got any meat?
Book 2 episode "The Library". Professor Zei (Head of anthropology at Ba Sing Se University) had some of the best parts:
Professor Zei: "According to legend it [the library] was built by the great knowledge spirit Wan Shi Tong, with the help of his foxy knowledge seekers." Sokka: "Oh, so this spirit has attractive assistants, huh?" Katara: "I think he means they look like actual foxes, Sokka." Professor Zei: "You're both right. Handsome little creatures!"
Then shortly after that, there is a scene that has a phrase I find highly amusing:
Professor Zei: "Tell me, sky bison, are you the last of your breed?" Appa: (Makes a guttural sound that means "Yes".) Professor Zei: "Delightful! I only wish I spoke his tongue! Oh, the stories this beast could tell..." Momo: (Starts to chatter at him in his own lemur tongue, in response to what the professor said.) Professor Zei: "Shush, chatty monkey."
Toph: "There it is!"
Everyone then goes to look to see nothing there. Toph: "That's what it'll sound like when one of you finds it." She waves her hand in front of her face to remind everyone that she's blind.
Her facial expression upon doing so.
Zei reaction to the (buried) library.
Professor Zei:(distraught) THE LIBRARY IS BURIED!? My life's ambition is now full of sand! (one second later) Professor Zei:(cheerfully pulls out a tiny trowel) Well. Time to start excavating.
One of the best moments is when Aang says that Appa can stay with Toph while they go into the library. They both look at each other, then look away, and then look back, before Toph casually says "What's up?"
One of the funniest lines is the nonchalant, sarcastic Owl-spirit who created and watches over the library talking to Sokka.
Wan Shi Tong: If you're going to lie to an all-knowing spirit being, you should at least put some effort into it.
It says a lot about Hector Elizondo's deadpan delivery that even "You're not very bright are you?" sounds funny.
"It's a... giant mushroom. MAYBE IT'S FRIENDLY!"
"Here mushroom! Mushy giant friend!"
"Why is Toph on fire?"
"How did we get here in the middle of the ocean?"
Not to mention his interactions with Momo, who has also sampled some of the cactus juice. "MOMO, NOOOO!!! YOU'VE KILLED US ALL!!!"
Katara: Sokka, let me see the things you got from the library. Sokka: What?! I didn't steal anything! Who told you that? (points accusingly at Momo) IT WAS YOU!!! YOU RATTED ME OUT!!! (Momo promptly begins crying, as if in admittance)
And after Sokka's cactus juice starts to fade...
Katara:(irritated) You’ve been hallucinating on cactus juice all day and then you just lick something you find stuck to the wall of a cave! Sokka: I have a natural curiosity.
Toph finally getting back on solid earth (sand doesn't count) and celebrating by making a snow angel in solid bedrock.
From The Serpent's Pass, Sokka, while Katara delivers a baby.
Sokka: "This isn't the same as delivering an Arctic Seal! This is a real... human... thing!"
"So do you want to go see the baby, or are you gonna faint like an old lady again?"
When the serpent appears in that episode, Sokka picks up Momo and holds him up and says, "Oh great and powerful Sea Serpent, please accept this humble and tasty offering. Thank you."
From "The Drill": "We lost." Oh Mai! Your comedic timing is impeccable!
"Just bend the slurry, woman!"
When they were on the train to Ba Sing Se:
Sokka: This is too easy. We'll probably have to fight some giant evil Fire Nation spoon next, or find that the city has sunk into a giant ocean filled with killer shrimp! Toph: [deadpan] You been hitting the cactus juiceagain? Sokka: I'm just saying! Weird things happen to us!
Then there was when the Earth King held a party for his bear. The humor came in the fact that the characters were confused not by the bear getting a party but by the fact that it was JUST a bear and not some weird mix.
Katara: The king is throwing a party at the palace tonight for his pet bear. Aang: Don't you mean platypus bear? Katara: No, it just says "bear." Sokka: Certainly you mean his pet skunk bear? Toph: Or his armadillo bear? Aang: Gopher bear? Katara: Just... "bear." Beat Toph: This place is weird.
After Katara and Toph head out dolled up as noblewomen, apropos of nothing Momo walks across the screen wrapped in a curtain, complete with gong sound.
"Lord Momo, of the Momo Dynasty. Your Momoness."
"Oh, Avatar Aang, how you do go on."
Then there's the bowing fight that ends up with Aang and Sokka knocking heads.
From the same episode:
(Bosco is eating everything in sight.) Earth Kingdom Guy 1: He's taking all the good stuff! Earth Kingdom Guy 2: Quiet! You don't know what I had to do to get seats this near the bear!
(Bosco jumps on table and continues devouring.)
The conversation between the sponsors, tea shop owner, and Iroh in the teashop, from the episode "Lake Laogai":
Tea shop owner: Mushi, if you stay, I'll make you...assistant manager. Wait. Senior assistant manager. (later, after sponsors promise lots of promises) Tea shop owner: Uh, senior executive assistant manager? Iroh: *hands teapot to the owner and accepts the promises* Sponsor: *to Zuko* That's right, young man! Your life is about to change for the better. Zuko: *deadpan* I'll try to contain my joy.
"Tales of Ba Sing Se"
"That's right, I'm Sokka, it's pronounced with an okka, young ladies, I rock ya!"
That's one too many syllables there, bub.
Plus the fact that a poetry club even has a huge, muscular bouncer.
Toph's absolutely magnificent bed hair.
The people at the spa trying to clean Toph's feet. It takes two people just to hold her down, then the room explodes. Also, Katara and Toph get a Cucumber Facial and Toph then used Earthbending to make the cucumbers stick out like alien eyestalks, terrifying one of the attendants.
When Aang finally gets fed up with all the rules in Ba Sing Se, he lets their tour guide know it, then declares that they're done following the rules. Toph's reaction to this? "Yeah! Let's break some rules!" Followed by her using Earthbending to blow up a side of their apartment building for no reason. (When they exit the building, they use the front door.)
The Gaang makes their case against Long Feng by bringing in Appa, with Aang sliding into two shots in a row like Bugs Bunny to point out how Appa's teeth and the bite mark on Long Feng's leg are the same shape. The Earth King says that they seem to be telling the truth (cut to the Gaang cheering), but this doesn't mean the rest of their accusations are true (cut to the Gaang looking depressed), but he thinks it's worth investigating (cut to the Gaang giving "That's...okay, I guess" gestures).
Xin Fu: I'm going to be stuck in here forever with you, aren't I? Beat Yu: I have to go to the bathroom. Xin Fu: * slams head into wall in frustration*
The Gaang coming back to save the Earth King's pet bear Bosco. Ty Lee is trying to teach it to walk on its hands. When Ty Lee falls into a bridge position, her hands and feet are suddenly encased in stones thanks to Toph's Earthbending. With Ty Lee out, they see the bear, then see Mai, who can't even be bothered to get up off of the steps she's sitting on. Her response? "...just take the bear."
From "Bitter Work," we have this little gem by Iroh and Zuko.
Zuko: "Now, I know what you're going to say: she is my sister, and I should try to get along with her--" Iroh: "No. She's crazy, and she needs to go down."
Right before then, after Iroh drinks Zuko's....poor imitation of his tea, he admits it is "bracing." Then Zuko gives him another cup, and the instant Zuko looks down at his own cup, Iroh chucks it out the window over his shoulder. A tiny moment but utterly hilarious.
All the more amusing when you note that this was seconds after she stole Aang's bag of nuts and gleefully abused his staff.
Aang getting hopped up on tea in the first episode. In normal benders, it increases their prowess, it increases their prowess tenfold, according to an Earth Kingdom general. Gilligan Cut to Aang Air Scootering circles around everyone present, all while asking whether or not it worked. He really can't tell right now. He then promptly smashes into a pillar.
From "City of Walls and Secrets," when Iroh and Zuko get jobs at the tea shop:
Iroh: Bah! This tea is nothing but hot leaf juice! Zuko: Uncle. That's what all tea is. Iroh: How could a member of my own family say something so horrible?
While "Appa's Lost Days" was 80% Tear Jerker and 19% Crowning Moment of Heartwarming, there's an absolutely hilarious moment when the leader of the sandbenders says they're going to sell Appa to "those beetle-headed merchants." That sounds like an insult about how stupid/gullible the merchants are...until they get to the merchants, whose hats, if you look closely, are shaped like beetles.
"I know you're not supposed to cry over spilt tea, but... (sniffs) it's just so sad."
Anything with Jet and Zuko. From the moment he meets him to the moment he is dragged off by the Dai Li, Jet is quite literally stalking Zuko. Made even funnier by how unnerved this makes Smellerbee and Longshot.
This shot [dead link] almost makes up for the crushing depressitude that made up the rest of the episode "Zuko Alone." Just look at how smug Azula looks, not to mention Zuko's dorky panicfais.
When Aang and Sokka return to Ba Sing Se in "The Crossroads of Destiny"
Toph: "Yeah, we wouldn't want those birds to hear us and turn us in." Sokka: "Hey! We're in enemy territory, those are enemy birds." *small bird lands on his head and squawks*
Half that episode is a CMoF, including this:
School Principal: Thak you so much for coming Mr...? Sokka: Fire. Wang Fire.[Strokes beard, gestures to Katara with a pillow in her jumper] And this is my wife, Saph Fire. Katara: Sapphire Fire, nice to meet you.
Earlier, there's a golden moment when Aang talks about what he did in school.
Aang: I've already gotten a picture of Fire Lord Ozai (shows poster), and here's one I made out of noodles! (shows noodle art) Sokka: Impressive, I admit.
Aang: You don't know what it's like, Sokka. You get to be normal all the time! Toph: Ha, ha!
The noodle picture makes a reappearance in "Nightmares and Daydreams": Aang sticks it on a tree and turns it into a dummy Ozai. "(flatly) The Fire Lord's defenses are impeccable."
Dock/Xu/Bushi from "The Painted Lady". At first, the appearance of Xu right after Dock is almost handwaveable - then the fact that they're the same guy becomes pretty blatant, to the extent that you fully expect him to Ass Pulla third personality. What you DON'T expect is for Aang to literally blow a fuse when it happens. There's even a puff of smoke!
What really sells it is the music playing in the background until he falls over.
A few bits of 'Sokka's Master' like the calligraphy and the painting, but also the bit where Sokka uses the rock garden to his advantage by... making himself a chair. And then Piandao goes along with it and asks his horrified butler to get him a drink, too.
The best part about the landscape painting is Piandao's bemused, "You added a rainbow."
Pure toilet humor, but in "The Runaway," when Sokka's picked up his new pet messenger hawk and discovers the group is in serious trouble....and then the new hawk craps on his hand.
Hard to forget the moment Appa was left in charge while Sokka and co. went off to scam. Everything between Momo, Hawky, and Appa is hilarious.
Later, "Katara! You're a genius! A sweaty, stinky genius!"
And one ep before:
Katara: Do they have toilets in the spirit world? Sokka: As a matter of fact, they do not.
Aang's call back to Sokka's name for Combustion Man before he got his actual nickname.
Aang: Sokka! It's Sparky-Sparky Boom Man!
Also from "The Runaway", Toph's blindness is played for laughs even more then usual.
Sokka: Toph, when I was in town I found something you're not going to like (unfurls a wanted poster) Toph: Well it sounds like a sheet of paper. But I guess you're referring to what's on the sheet of paper. (Minutes later)
'Katara: ...Well then, what's this? (brandishes the same wanted poster) Toph:(seriously irritated) I don't know! I mean, seriously, what's with you people?! I'm blind!
And minutes later after that, Aang an Sokka try to patch things up between Toph and Katara by giving Katara a fake apology letter.
Katara: I know this is from you, Sokka! Toph can't write! Ugh, you're all driving me crazy! Aang: I can't believe we forgot Toph can't write. Sokka: Yep, we're idiots. Aang: I guess plan B is, we send a note to Toph pretending it's from Katara. Sokka: I think we're gonna run into a similar problem.
Every moment of Azula trying to fit in socially in "The Beach", particularly her attempts to get a guy to like her.
[A groggy host finds Azula and company at his door] Host: What are you doing here? Azula: You said we'd be partying from dusk to dawn. It's dusk, so we're here. Host: That's really more of an expre- Azula: We are the perfect party guests. We arrive right on time, because we are very punctual.
And this gem:
That's a sharp outfit, Chan. Careful, you could puncture the hull of an Empire-class Fire Nation battleship, leaving thousands to drown at sea... Because it's so sharp.
Followed shortly by Azula and friends destroying and burning down Chan's house as payback for the various problems they had at the party. Who knew raging sociopathy could be so amusing?
The Pastel Freeze Frame that makes up the end of the episode. Mai, Zuko, Azula and Ty Lee sharing a tender moment as the house burns down behind them...complete with Ty Lee sporting a frighteningly huge shit-eating grin.
Also her ability to make even volleyball Serious Business on par with her usual war-waging:
Yes! We defeated you for all time! You will never rise from the ashes of your shame and humiliation! [pause] Well, that was fun.
Azula: Well yes, I guess you're right. I don't have sob stories like all of you. I could sit here and complain how mom liked Zuko more than me, but I don't really care. (frowns and looks down at the fire) My own mother thought I was a monster...
(Beat Azula: She was right of course. But it still hurt.
Though the Azula scene crossed over into a bit of a Tear Jerker thanks to her story.
Actually, just that whole episode. Zuko's flashbacks were quite touching, but they lose some impact when they're in the same episode as the dramatic shirt-toss with Disturbed Doves. Or Zuko almost throwing up thanks to Lo and Li. Or the Serious Business volleyball game. Or Mai being... Mai.
Zuko and Mai's fizzling relationship in the first half of the episode was pretty hilarious. The two were both so bored and deadpan.
Zuko: It's hot, so I brought you this. (Zuko holds out an ice cream cone, which promptly falls on Mai's leg.) Mai: ...Thanks. That was really... refreshing.
When Aang discovers a nice bed made of wool by his friends, there are naked, miserable, shivering sheeps next to Sokka.
Also this scene where Zuko wants to walk to Mai's house, his palanquin bearers insist that a prince must not walk anywhere, even though he tells them it's not very far. They then carry him for about 10 metres to where Mai's waiting for him.
Sokka starting from the beginning while presenting his battle plan. "So Katara got Haru and his father out of jail. He's got a mustache now."
Haru's mustache itself qualifies.
"Then Suki dressed me as a woman and she kissed me..."
During "The Eclipse" when the Gaang is looking for Ozai's chamber:
Toph: I'll be able to tell when you're lying! Azula: Are you sure? I'm a pretty good liar. *completely with a straight face* I am a four-hundred-foot-tall purple platypus-bear with pink horns and silver wings.
*Beat* Toph: ...Okay, you're good, I admit it.
"Hello! Zuko here!" And basically any other time Zuko shows off his dweebery after joining the group... "Silver Sandwich" speech, anyone?
Zuko: We're the Fire Prince and the Avatar. I think we could take these guys in a fight whoever they are. (The firebending masters turn out to be dragons.) Aang: Still think we can take them? Zuko: I never said that!
The Sun Warriors prank Aang and Zuko into thinking they'll never be allowed to leave after discovering the warriors' existence. "Just kidding! But seriously, DON'T TELL ANYONE!"
Aang: Hey, Zuko! Come over here! I want you to dance with me! Zuko: O_o;
A bit earlier, Zuko realizes the Sun is the true source of firebending. "Do you guys realize this?" "Well, we're called the Sun Warriors, so yeah."
Zuko: It's not a dance, its a Firebending form. Sokka: We'll just tapdance our way to victory over the Fire Lord. Zuko: It's a sacred form that happens to be thousands of years old! Katara: Oh yeah? Well, what's your little form called? Zuko:...The Dancing Dragon.
Zuko: Well, I did have a girlfriend. Mai. Sokka: That gloomy girl who sighs a lot? Zuko: (dreamy face) Yeah...
The Warden singling Hakoda out for abuse, only to be stubbornly ignored. Once he does look the warden in the eye, Hakoda trips him up with his handcuffs.
Back in 'The Serpent's Pass', Suki gets Sokka to recognise her by kissing him. When he walks into Suki's cell, he tries the same thing in reverse. Except that with his visor covering his face, Suki does not recognise him and so punches Sokka into the door. Even better, when he's later delighted to find his dad he starts talking to Hakoda with his helmet still on. Hakoda thinks it's a random guard taking the piss and almost punches him;
The show's Mix-and-Match Critters are always good for a laugh, but easily the funniest is an off-hand reference Aang makes during "The Old Masters" to "the spider-fly, caught in its own web!"
Avatar Extras notes that the spider-fly is the most contradictory animal in the Avatar universe.
Directly after Toph and Zuko's heartwarming moment.
(Toph elbows Zuko hard) Zuko: Ow! What was that for!? Toph: That's how I show affection.
From "The Phoenix King":
Toph: Hey, wait a minute, has anyone noticed that Momo's missing too? Sokka: Oh no! I knew it was only a matter of time. Appa ate Momo! (starts climbing into Appa's mouth) Momo, I'm coming for ya, buddy! Katara: Sokka, Appa didn't eat Momo. He's probably with Aang. Sokka: That's just what Appa wants you to think. Zuko: Get out of the bison's mouth, Sokka.
Toph's insistence on going with Zuko to search for Aang because "everyone else got a magical, life-changing field trip with him!"
Made even funnier by Zuko blushing as she hugs him.
Another one from "The Phoenix King" is Toph's quick moment of in-universe shipping:
Katara: I have a surprise for everyone! Toph: I KNEW IT! You -did- have a secret thing with Haru! (grin) Everyone else: (WTF looks) Katara: ...Um, no.
Just about anything Bumi ever says is guaranteed to split at least one person's sides:
Bumi: Wait! Someone's missing from your group! Someone very important. Beat Where's Momo?
Zuko accidentally calling Ozai the Fatherlord.
During the four-part finale when Sokka dumps an entire Fire Nation airship's crew into the ocean after luring them to the bomb bay under the guise of holding a birthday party for a crew member. Made even funnier by the ludicrous coincidence that it was actually someone's birthday.
Crew Member: I can't believe the captain remembered my birthday! He really does care! Other Crew Member: [after being dumped into the ocean] Happy birthday.
Plus the awkward conversation between two people from different sections who've never met.
Quin Lee: Hey, I'm Quin Lee. I work up in communications. Crew Member: I work in the engine room. ...That's probably why we never met before.
Earlier, when Toph knocks on the door, using the last beat in the shave-and-a-haircut rhythm to smash it off its hinges.
Later during that scene, after Aang begins his battle with Ozai, Sokka has a few shifts in his mood:
Sokka: Go, Aang! Airbending slice! (makes chopping action) Suki: Shouldn't we be helping him? Sokka: (thinks about it for a second and gets serious) The Fire Lord is Aang's fight. We need to stop those airships from destroying the Earth Kingdom. Toph: (as Sokka moves to look out the window towards the airships behind him) And how do we do that, Captain Boomerang? I can't see outside this giant hunk of metal. Sokka: (turns back to the others gleefully, making another chopping motion) Airship slice!!
Azula: (points to Li) Lo, you are banished. (to Lo) Li, you may stay. [Exit] Li: But...I'm Li. So which one's banished? (Lo shrugs)
Mai and Ty Lee each get one in the finale, with oddly similar reactions.
First, Mai reunites with Zuko, and after a short conversation abruptly does a Mood Whiplash and threatens "But don't you ever. Break up with me. AGAIN." Cue Zuko giving a nervous smile that just screams "Sorry, please don't kill me."
Next, Ty Lee has joined the Kyoshi warriors and talks about how they'll be best friends forever. She then wraps two of them in a headlock hug. The two just smile as wide as possible just like her. Oh no! Ty Lee has turned the Kyoshi warriors into the worset thing possible... Ty Lee CLONES!!!
Ozai's Oh Crap face, when being yelled at by the Avatar for the crimes he's committed, makes it look like he's crapping his pants in fear. While it sounds like it makes you laugh in the "pure Narm" sense, it really makes you laugh in the "Oh hell, he knows he's screwed now" sense.
Before, when he looks down into the rubble where Aang lay, in the midst of a grandiose and bombastic speech...which is cut off with a loud "gyack!" when Aang's hand shoots up and snatches Ozai by the goatee.
Even though "The Puppetmaster" was, for the most part, utter Nightmare Fuel, there's a couple of darkly funny moments. For example, when Katara says that Hama reminds her of Gran Gran, she holds up a head of cabbage that looks like Gran Gran's face.
Suki walking up to and pointing at Ozai, slumped against a rock, and wondering whether Aang killed him. The Phoenix King raises his head to inform her; "I'm still alive."
Quite a few in "Nightmares and Daydreams"
"We all died because of your tiny bladder!" - Aang explaining a dream where Toph had to go to the bathroom in the middle of a battle.
"Want to try screaming into this pillow?"
Azula's whittling down of her subordinates by banishing them over the littlest issue. It's darkly funny in the same way Darth Vader ran through his admirals in The Empire Strikes Back.
This one moment in Sozin's coment where Sokka takes stupidity to a new level. When Toph points out Momo is gone as well.
Sokka: Oh no...I knew it was only a matter of time. APPA ATE MOMO! Momo, I'm coming for you buddy.
Even funnier is that he then gets into Appa's mouth and tries to convince the others about it. While everyone's discussing searching for Aang, in the background we see Sokka being spat out covered in saliva. He gets up wiping himself and then falls back into it again.
When it's decided that the rest of the gaang will help Aang fight Ozai, a group hug is initiated...except for Zuko, who's never been into that stuff, even after joining the good guys. Katara calls Zuko over, and as he reluctantly does so, Appa decides that he wants to join the group hug too!
Even the "Avatar Extras" have their moments of hilarity. In "The Drill", there is a brief scene in pitch darkness. During this scene, a box pops up that says "This was the easiest scene in the episode to animate."
"Bitter Work": "'Like A Rock' was a song by Bob Seger. It was in a lot of commercials. Aang doesn't watch commercials. He's kind of busy."
Another good one is when the Gaang has found that all the information in the spirit library concerning the Fire Nation has long since been destroyed.
"Firebenders fight dirty. Earthbenders fight with dirt."
Aang and Zuko actually have more in common than they know. For one, they're both bald, if you don't count Zuko's firebender ponytail.
After King Bumi welcomes the Gaang to "old people camp."
Dinner at 4 o'candle. Bedtime at 6 o'candle.
The chibi-style bonus story in The Lost Adventures, where under the guidance of Avatar Kyoshi, Aang and Azula pick out teams for a game of dodgeball. Azula gets last pick of Zuko or Mai. She goes for Mai. Zuko angrily asks what he's supposed to do. Kyoshi's reply? "You're the ball!"
Sokka's attempts at adjusting Earth King Kuei's pet bear Bosco to a life in the wild (also from The Lost Adventures), causing him more and more frustration with every attempt.
Sokka: In order to defend one's territory, you've got to sound really ferocious. So give me your most frightening roar. King Kuei: Um, Bosco doesn't roar, but he's a lovely whistler.
First CMOF of the interquel:
Katara: (Hugs Aang) I just hate seeing you get like that, sweetie. Sokka: Um, Aang? Katara? You're giving me the oogies over here! Katara: Aargh! I am so sick of hearing about your stupid "oogies," Sokka! I don't even know what that means! Toph: I can explain. Give me your hand. Katara: (Gives Toph her hand) Toph: Gaaah...(Licks Katara's hand) Katara: ! Distant Reaction Shot: OOGIE!
Best part is how Toph apparently has Gene Simmons' tongue. Slides it riiight up Katara's ring finger.
"You know what fireworks are like for me?" *Toph screams in Sokka's ear*
Toph's blind gags; either pretending she can see...
Toph: [Concerning a (supposed) sketch of Appa] It looks just like him to me! Sokka: Thank you, I worked really... why do you feel the need to do that?
Especially funny given that she was on the other side of the room and couldn't have looked at it yet even if she could see.
Katara: Got something against libraries? Toph: I've held books before and I gotta tell you, they don't exactly do it for me. Katara: Oh...right...sorry. Toph: Let me know if they have something you can listen to!
In "The Drill", after Toph pulls the Gaang underground we get this exchange:
Sokka: It's so dark down here. I can't see a thing. Toph: Oh no! What a nightmare! Sokka: ... Sorry.
When Sokka and Aang are trying to get Toph and Katara to stop fighting, they send a make-up letter to Katara pretending it was from Toph.
Katara: I know this is from you, Sokka! Toph can't write! You're all driving me crazy! Aang: I can't believe we forgot Toph can't write. Sokka: Yep. We're idiots.
[beat] Aang: I guess plan B is, we send a note to Toph pretending it's from Katara. Sokka: I think we're gonna run into a similar problem.
Any of the Foamy Mouth Guy's appearances.
In the animated short "School Time Shipping", Katara ends up with... The Blue Spirit. Zuko's reaction is hilarious.
"I did not see that coming."
The final message of the Avatar Extras version of the series gives a nod to the Ship-to-Ship Combat and a Take That to the Zutara ship as Aang and Katara share a kiss.