Prince Charming's speech in the beginning of the movie, rallying the downcast villains into taking their happily ever after into their own hands.
When Artie gets picked on by the students, Donkey, of all people (having been stuffed into a locker and having a "I sucketh" note planted on his butt), snaps at them, "Ya'll should be ashamed of yourselves!" Defied quickly when Lancelot says "That wasn't me." Still, having a funny talking donkey standing up against the bullies is kinda cool.
Before leaving with Shrek, Donkey, and Puss, Arthur gives a major "The Reason You Suck" Speech to his entire school and promising payback to Lancelot and his bullies.
What sells it is Pinocchio's demeanor throughout the scene. He starts out uncertain, as if he just thought up with the strategy then and there, starts to roll with it when he realizes that it's working, then has a very confident grin on his face as he keeps the charade going. Had the three little pigs not succumbed to said Confusion Fu themselves and squealed, Charming would probably have given up and left with no answers at all.
Arthur managing to guilt trip Merlin.
There is the scene when Queen Lilly breaks all of the princesses out of jail- by knocking down a stone wall with her head. Twice. She summarizes her amazing skills in one simple quote.
Queen Lillian: "Well, you didn't actually think you got your fighting skills from your father, did you?"
Followed by a Crowning Moment of Funny when the dazed Queen (played by Julie Andrews) has to be helped up and led away...but she's singing to herself, "Raindrops on roses and whiskers on kittens..."
The fact that Fiona escapes prison and leads the princesses on an attack against Charming to rescue Shrek while pregnant is pretty amazing.
While being stuck in Charming's twisted play, chained, and about to be gutted, what does Shrek do? Making fun of the loon, and even making his minions laugh. There's Defiant to the End, and there's mocking your captor, all with a mocking smile.
Even if it was made just to kill Shrek, the fact that the villains were able to put on such an elaborate play, with a large set, songs, and choreography, all in a matter of a few hours is pretty impressive.