Zhang Fei standing on a bridge and driving back the entire opposing army just by shouting at them - killing an enemy general through fright in the process.
There's also Zhang Fei's cleverest moment. Zhang is sent to take a land route to help relieve Liu Bei, while Zhuge Liang and Zhao Yun go by water. Along the way, Zhang is forced to besiege a city on the route. After a couple failed ruses, Zhang manages to feed some enemy spies false information, causing an unwise attack by the defenders and the fall of the city. Capturing the governor (Yan Yan) alive, Zhang manages to talk him over. With Yan Yan's help, Zhang then manages to take 45 separate garrisons without a fight. This gets him to the main engagement quickly enough that he can swoop in with a Big Damn Heroes moment. The best part is that Zhuge Liang expected to get there first, so Zhuge's shock at being beaten is hilarious.
Guan Yu calmly playing a game of go with one arm while the other is operated on without anaesthetic.
Guan Yu plowing his way through six generals and their five "gates" (checkpoint forts) on his journey to meet back up with his sworn brother Liu Bei... only for Cao Cao, whose service he'd been leaving, to let him keep the famous stallion Red Hare (after Guan Yu had explicitly said that he would use it to reach Liu Bei!), offering him gold to cover expenses and then a robe when that was refused, and letting him off the hook every step of the way (except by not giving those commanders the heads up...). Oh and by his sheer awesome he gets a would-be ambusher to betray the plot and gets followers, including Zhou Cang and Guan Ping (portrayed alongside him in many a depiction) and later Zhao Yun, in the course of things! (The "awesome" is mildly averted posthumously, when a priest who in life had warned him of an ambush by one of those generals, then calls Guan Yu's ghost on them and all of his other victims.)
Diao Chan manipulating Dong Zhuo and Lu Bu into fighting each other, after numerous armies could not defeat their combined forces. (It should be noted that this is quite pivotal to the story's beginnings.)
Zhuge Liang is basically a living embodiment of CMOA. Everything he does until his failed final campaigns against Wei (whose failure was not his fault at all) kicks ass. Including his death, where in Chapter 104 his wooden statue scared Sima Yi into holding off an attack long enough for the Shu army to retreat.
He taunts a Wei official to death during a parley with their armies lined up facing each other (complete with Zhuge Liang explicitly declaring in the conclusion that his seventy-six year old opponent will die that day). The subsequent troucing of the enemy army does bite him in the ass though, as the Wei emperor listens to one of his ministers and recalls Sima Yi (framed by Zhuge Liang to keep him from command) from semi-retirement.
There's also the time the time in Chapter 95 where in response to Sima Yi's march towards the city of Xicheng and Zhuge Liang's army of 2,500 outnumbered 60 to 1, he publically sits on the castle wall playing the lute as if nothing is wrong, the city with its gates thrown open and completely defenseless... but thanks to Zhuge Liang's reputation as a military commander and strategist, Sima Yi fears an ambush and turns his 150,000-man army around.
This also works because Sima Yi knows that in Zhuge Liang's long career he's mastered ambushes, fire, hiding his numbers, and snatching victory from the jaws of overwhelming odds again and again and again, but he has never, ever bluffed.
And the time before his death (also Chapter 104) when he orders the army not to mourn, so that his star will not fall, held up by his ascended spirit and thus keeping Sima Yi fearful and suspicious. Even when it does fall, Sima Yi fears that Zhuge Liang simply got the gods to fake it and thus doesn't attack in force.
To this troper's knowledge, only Liu Qi (in one of the more strangely humorous moments in the story) and Jiang Wei ever preempt and surprise him.
Actually, in Chapter 102, Zhuge Liang comes up with a plan to attack across the River Wei and Sima Yi sees through the plan completely and beats it back at every turn, costing Zhuge ten thousand soldiers. Just a temporary setback, but still, for anyone to get the best of him like that automatically makes it the CMOA for the other guy.
Zhang Fei also gets the drop on him, turning an enemy officer to take numerous passes with such speed that he actually manages to get to the pivotal battle point first. See above.
Jiang Wei, just for holding his own against Zhao Yun in personal combat and actually confounding Zhuge Liang in the field; Zhuge Liang acknowledges his genius and ends up having to concoct a scheme involving Jiang Wei's mother, an escaped prisoner, and even a body double to finally corner Jiang Wei. When he surrenders, Zhuge Liang declares that he's finally found a protege who can inherit his knowledge and legacy.
Dian Wei holding off an enemy ambush to let Cao Cao escape: Drunk (thanks to the enemy) and with his halberds and armor stolen while he was away, he grabs an infantryman's sword and kills people until it breaks, then grabs some enemy soldiers and continues. Nobody dares to pass his corpse, still "warding" the main gate, and Cao Cao lives to fight another day.
There was also the time that before this he once fought his way into Puyang city (after an ambush by Lu Bu's forces) to rescue Cao Cao, fought his way out without finding his lord, and then fought his way back in to have another go... twice.
Zhang Liao (of Wei) holds off the Wu army: 800 against 10000 (historical records claim 7000 versus 100000), and nearly takes Sun Quan's head in the process. Not to be outdone, in the next engagement, Gan Ning (of Wu) proceeds to round up 100 of his best men, raids the Wei encampment and comes out without a single casualty.
Gan Ning was also a badass at the battle of Huancheng, where he climbed a castle wall (while fending off arrows with a chain). He used said chain to capture an enemy commander, pulling him off the wall.
Lu Bu. And by extension, Zhang Fei, Guan Yu and Liu Bei, simply for fighting him to a draw at Hu Lao Gate.
On the battlefield in duels, anyway. When it came to strategy/tactics, or off the battlefield... not nearly so much. (Correspondingly, in the video game series of the same name, he is far less "broken"/useful than in the Dynasty Warriors series. This troper has (as Cao Cao) held off multiple invasion attempts by Lu Bu in Romance of the Three Kingdoms XI just by having units cast Misinform... causing him to turn around and go back the way he came every time.)
Lu Bu: Mighty warrior, peerless archer, backstabbing SOB, bloody idiot.
Cao Cao is typically portrayed in the novel as a mere Smug Snake, but his Crowning Moment of Awesome was at the Battle of Guan Du, where he beat Yuan Shao's forces through strategy despite being outnumbered 10 to 1.
And then there's his lies! He tried to stab Dong Zhuo in the back with a really pretty-looking short sword, but was a bit too slow to pull it off. When Dong Zhuo turned around and saw Cao Cao leaning over him with a weapon, Cao Cao told him he wanted to give it to him as a present. Dong Zhuo gifted Cao Cao with a horse, which Cao Cao promptly used to escape. Even Lu Bu thought that Dong Zhuo was having a dumb moment there.
A battle of smarts between Cao Cao and Lu Bu isn't going to be a clash of the titans. In the same battle where Dian Wei nearly burned to death trying to find Cao Cao, Lu Bu was hunting him in the streets. He actually captured Cao Cao but didn't recognize him (he saw him before, see above). He actually asked Cao Cao where Cao Cao was. Cao Cao pointed at some random guy on a horse, and Lu Bu sped off in pursuit.
Mi Heng, although he's only in Chapter 23, is stupendous. Prime Minister Cao Cao solicits Kong Rong to provide a famous scholar to be his envoy, so Kong Rong provides a flowery testimonial to the Emperor hyping up 24-year-old Mi Heng. However, since he's not invited to take a seat, he starts tearing the hell out of Cao Cao's officers, by name and in detail. Cao Cao decides to make him a drummer boy to mortify him (and spare himself any fallout from killing Mi Heng), but at his first performance he first shows up in old robes, then he drops them for his birthday suit to show his "purity" while tearing Cao Cao himself for his jerkassdom... oh, and not giving Mi Heng a better job. Finally, when he's "drafted" back into that messenger role, he insults those same officers to their faces as he's led off on horseback. Ironically, he then goes on to roast the target of his 'diplomacy,' and is only spared to leave his host's hands clean (the host recognizing that Cao Cao's using him as a scapegoat should Mi Heng die). It finally takes a third 'host' to finally decide to off him, after he and Mi Heng became intoxicated and had an unfriendly "discussion"... Mi Heng literally spending the rest of his life insulting the guy. He's then honorably interred by that second host on Parrot Island.
The line which got Mi Heng killed? His description of his third host: "You are like a god in a temple: You sit still and receive sacrifice, but the lack of intelligence is pitiful."
Ma Chao, a spear-wielding badass who ended up working for Liu Bei, defeated a Cao Cao army through simple tactics (eg taunting) after Cao Cao did something foolish (killing Ma Chao's family members). When Cao Cao sent a real army to stop him, Ma Chao outfought several of Cao Cao's top champions. Cao Cao couldn't outfox him in the field, and almost got captured in combat, but did manage to convince five of Ma Chao's compatriots to try to kill him. Ma Chao was forced to fight them off by himself with a sword (not his best weapon), and he still killed one and wounded another, prompting the rest to run for their lives.
Xu Chu vs. Ma Chao. The two fight for over a hundred bouts with no clear victor, to the point where they each have to switch horses several times. Then Xu Chu, just to be badass, strips off his armor and fights naked.
Sun Ce is the only warlord to realize that the Imperial Seal is just a symbol and holds no real power, so he trades it Yuan Shu for 3000 troops, and proceeds to conquer the Southlands with them.
Sun Ce's army was being taunted by an officer of inconsequential rank while they laid siege to a city. While taunting, the officer's hand is resting on a beam. Taishi Ci decides not to take this anymore, and shoots the guy through the hand with an arrow, pinning him to the beam. Even more awesome: he called the shot ("Watch me hit his hand") before making it.
Sun Ce gets ambushed and a guy shoots him in the cheek with an arrow. Sun Ce pulls the arrow out, takes out his own bow, shoots the arrow back at the guy, and kills him.
Hao Zhao holds off Zhuge Liang's forces with a mere three thousand men. One-Scene Wonder, indeed.
Zhang He slashes his way out of Zhuge Liang's ambush, and then goes back in to rescue his buddy. Zhuge Liang watches from afar, and is impressed.
The otherwise insignificant Liu Qi, one of Liu Biao's would-be heirs in the whole Jingzhou brouhahaha, wanted Zhuge Liang's advice to get through the impending succession crisis, but Zhuge Liang wanted none of it, especially since he was serving Liu Bei who refused to simply take the damn thing. As a result, Liu Bei secretly told Liu Qi that Zhuge Liang would help, and pretended to be ill so as to force Zhuge Liang to go. When Zhuge Liang saw Liu Qi, he was repeatedly beseeched to help and kept there, finally being lured into an attic where he was begged for again...
Zhuge Liang flushed and rose to go away. But he found the ladder by which they had mounted had been removed.
For a character who only appears in one paragraph, Wu Fu manages a hell of a CMOA. He tries to stab Dong Zhuo with a knife, but Dong and Lu Bu stop him.
Dong Zhuo: Who is behind this treason?!
Wu Fu: You are not my sovereign. I am not your subject. What "treason" are you talking about? Your crimes tower to Heaven, and the whole world longs to see you dead. My only regret is that I cannot have you pulled apart by horses - like any traitor - to satisfy the realm.
Dong Zhuo then has Wu Fu dragged out and tortured to death, and Wu Fu never stops cursing him.
In the face of execution, Zhang Liao keeps his pride and actually taunts Cao Cao, unlike Lu Bu, who tries to beg for his life. Then of course, Zhang Liao is the one spared and Lu Bu gets the rope.
Taishi Ci comes to mind. He rushes to the aid of a man he has never met, because said man was nice to his mother. Later, he battles Sun Ce (the same man who, well trying to flee with a prisoner, accidentally killed the prisoner with his armpit well ramming a spear through another officers face) by drawing him away from his officers for a proper duel. When Sun Ce latches on to his spear with his man crushing arms, Taishi Ci rips Sun Ce's helmet off and uses it as a shield to fend off Sun Ce's attacks. To top it all off, barely a few pages later, he spots an enemy leaning against a pole with one hand in the distance. He decides the best course of action is to fire an arrow through his hand, pinning him to the pole.
This troper has always considered the minor Wu officer Kan Ze's only major role to be a CMOA. Why? At Chi Bi, Huang Gai has the task of making a false defection to Wei in order to set fire to their ships. He has his old friend Kan Ze deliver the letter to Cao Cao. He does so, but Cao Cao believes it to be a trick (which it is), and orders for Kan Ze to be beheaded. Kan Ze's response? He laughs.At Cao Cao. And when Cao Cao asks why, Kan Ze starts insulting him.
Kan Ze: I am so glad you are not frightened but can still boast of your knowledge of the books of war. Now you will not lead away your soldiers. If you fight, Zhou Yu will certainly capture you. But how sad to think I die at the hand of such an ignorant fellow!
And when a confused Cao Cao asks why he is happy at the scheme being found out, Kan Ze then proceeds to explain how the letter and defection are 'real'. While still insulting him.
Kan Ze: Do you not know that when one is going to desert one's master and become a renegade, one cannot say exactly when the chance will occur? If one binds one's self to a fixed moment and the thing cannot be done just then, the secret will be discovered. One must watch for an opportunity and take it when it comes. Think: Is it possible to know exactly when? But you know nothing of common sense. All you know is how to put good people to death. So you really are an ignorant fellow!
But the icing on the cake? Cao Cao ends up believing him, and lets him return to the Wu camp to help Huang Gai in his 'defection'. Which means that without Kan Ze, the Wu-Shu victory at Chi Bi might have never happened.
Another CMOA comes from Chapter 33, and is performed by Wei strategist Guo Jia (who some believe had the potential to match the likes of Zhuge Liang and Sima Yi). Two of Yuan Shao's sons, Yuan Xi and Yuan Shang, have fled to Liaodong, ruled by Governer Gongsun Kang. Meanwhile Guo Jia has just passed away, but has left a letter for Cao Cao. Cao Cao reads it, but keeps the contents secret. Many of the Wei officers then repeatly asks Cao Cao why he doesn't attack the two Yuans and Gongsun Kang before they become a threat. Cao Cao merely tells them all to wait. A few days later, there arrives for Cao Cao a wooden box, sent by Gongsun Kang, containing the heads of Yuan Xi and Yuan Shang. The officers of Wei are surprised, but Cao Cao merely presents to them the contents of Guo Jia's dying letter:
Yuan Xi and Yuan Shang are going to Liaodong. Illustrious Sir, you are on no account to attack, for Gongsun Kang has long lived in fear lest the Yuans should absorb his country. When they arrive, Gongsun Kang will hesitate. If you attack, he will save the Yuans to help him; if you wait, they will work against each other. This is evident.
Cao Cao even says in Chapter 50 that had Guo Jia still been alive, he would not have lost at Chi Bi:
Line 86: As Cao Cao drank among his familiars, he became exceedingly sad. 87: Wherefore they said, "O Prime Minister, when you were in the cave of the tiger and trying to escape, you showed no sign of sorrow. Now that you are safe in a city, where you have food and the horses have forage, where all you have to do is to prepare for revenge, suddenly you lose heart and grieve. Why thus?"
88: Replied Cao Cao, "I am thinking of my friend Guo Jia: Had he been alive, he would not have let me suffer this loss [at Chi Bi]." 89: He beat his breast and wept, saying, "Alas for Guo Jia! I grieve for Guo Jia! I sorrow for Guo Jia!"