Charlie Chaplin in Modern Times in the first factory sequence when the pressures of that inhuman factory floor get too much and the Tramp goes berserk like a loony ballet dancer throwing the plant into chaos.
Chaplin has so many moments to choose from, but for me it's got to be the Mutual short, "The Adventurer", when fugitive Chaplin scribbles over his mugshot in a paper, and the police think it's antagonist Eric Campbell. It's so ridiculous it's brilliant.
Gold Rush. The Tramp is stuck in a cabin during a blizzard with two huge mountain men: as tensions run high, the two come to blows, and end up spinning in circles as they grapple for a shotgun - the barrel of which follows Chaplin all over the cabin as he tries to find cover. Watching Chaplin practically climb the ceiling to get away from a seemingly-sentient shotgun is just awesome.
The boxing fight in City Lights, with the Tramp keeping the referee between himself and the other boxer for the whole match, occasionally reaching over to take potshots at him.