The breather episode "Revved Up" has several. Starfire and Raven pretending to be the evil "Dr. Mumgam" and "Henchy" with Starfire failing at it, and then the wrecked T-car going through a tunnel and emerging from it as Cyborg on a single axle with Beast Boy as a horse on the reins.
From "Every Dog Has His Day", Starfire & Raven are focusing on a crystal ball, with Raven describing how they:
Raven: Need peace, and absolute-"
(Beast Boy's head appears warped, on/in the ball): DUDES!!
(the girls scream and clamp onto each other)
What, no love for the episode starring Robin's inter-dimensional counterpart, Larry? When they wind up breakingreality, Beast Boy loses his mouth, and steals Raven's so that he can speak. Then SHE steals Cyborg's...then HE steals Starfire's. I do wonder how the voice actors avoided cracking up, especially Cyborg's having to imitate Raven's deadpan-ness.
Also would be Larry's excitement over his new moniker, saying his name over and over again while doing er...interesting things with the titans.
From "The Quest" - "The mask makes me feel cool, too."
"Did you NOT see the movie? When you split up the monster hunts you down one by one. Starting with the good-looking comic relief guy...ME! And I'm probably delicious!"
"I'd like to go to jail now, please."
The entirety of "Lightspeed".
Another one: While Robin is away seeking training, the other Titans raid his room and start wearing his spare costumes, till Raven walks in, and says, "This is just disturbing" - after which she of course joins in, only to have Robin himself walk in...it just really works.
The beginning of "The Lost Episode" has Robin and Cyborg playing a video game, Starfire cooking alien food, and Raven reading her book when Beast Boy comes in with a boombox turned up loud and decides to crank it up more by plugging it into the main power grid, which causes everything to go haywire and the tower loses power and everything goes dark. In great Steve Urkel fashion, Beast Boy says "Did I do that?"
From Revolution: "I'm American!" "You're welcome."
Commentator:Oh, hoho, that had to hurt! Let's look at the replay, Chuck! You know, I'm not sure why a Teen Titan in on the field at the Championship game, but this is just a great defensive play by the Steel City Tigers.
Starfire in the Dr. Suess-esque cartoon, rhyming along with the characters.
Pelican: Oh have you seen my hippo? He hides and I must seek!
Starfire: I cannot play, please do you know a strange man named Control Freak? He is big, not tall, and nasty, and know for causing strife. He escaped into the TV-
Beast Boy(while being chased by a laser shooting robot): HEY STAR, RUN FOR YOUR LIFE!
Robin: -REALLY makes a forced, wide smile- -cracking sound effects- Maybe.
Starfire makes the best faces in that episode. The best one comes when she's at the punch bowl and some poor sap makes the mistake of asking if she can move so he can get some punch. It has to be seen to be believed.
In "Transformation," as Beast Boy desperately waits to use the bathroom he is exposed to, among other things, Robin performing the classic garden hose gag, followed by a baffled Aside Glance. Then there's Cyborg pouring himself a glass of water from the sink. Shortly after we see Raven moving two rocks to let water pass mimicking the same gag but from a "female" perspective.
"L, M, N, O, PEEEEEE"!
"This is the greatest pie. In the history of pie."
Starfire: Oh, hello long-lost friend!! You remember me, yes?
Terra: Of course, Starfire. I still have bruises from the last time you hugged me.
Pretty much everything Beast Boy and Cyborg do in "Stranded," highlights being Beast Boy turning into a wookiee and Cyborg resigning to BB's inability to understand scientific terminology, telling him to "pull the red candy cane thingamozy."
From the same episode we have the adorable little alien thingies that worship Raven, constantly going, "Shala!!"
Robin and Starfire have some of the best interactions
Robin: SHE'S NOT MY GIRLFRIEND!
Starfire: I am not your friend?
Starfire: I am not a girl?
And date with destiny:
Killer Moth: And Robin... will take this lovely young lady to her junior prom.
Kitten: Hi Robbie-Poo.
Robin: Uh, what was that last one?
Starfire: Robin, who is this girl? And why does she call you "poo"?
Robin's reactions to Starfire's line are hilarious.
Even in the depths of rage and jealousy, Starfire does not once break from her speech pattern:
"Odium! Scandal! Atrocity! These demands must not be met! -Snip- Out of his mind if he thinks you would even consider such a distasteful-!"
Mumbo calls for a lovely assistant from the audience and yanks Starfire down with a cane. He then assembles a "sawing-a-woman-in-half thin-model box" around Starfire. As he prepares to perform the "trick", he adds: