Winston's Noisy Shut Up in "Secrets," where he gets the entire apartment to shut the hell up (and simultaneously solve all of their arguments). And why'd he do it? Because it's Saturday. That's a sleeping day.
Nick punching out Taye Diggs' character after finding him naked in Jess' bed. Especially great because it looked like Nick was going to comedically get taken out in a drunken stupor.
Schmidt impressing Sadie with his sexual prowess using a vagina diagram and some Unusual Euphemism.