Harris: And yes we meant skillz, and not skills... 'Cause we're... Thirty-three-T... Thirty-three-T? Leet! Yes... With two three's instead of two E's. Okay. And yes we meant skillz, and not skills. 'Cause we're L33T.
Because of the way network play is handled, online games can become funny if you host one with voice chat using an outside program like Skype. You'll often hear a player scream in frustration seconds before you actually see them mess up their turn.
The Worst Shot Ever contest. Watching these people backfire so horrifically is hilarious.
The mission fail screen from 3D which starts out as a tear jerker of an angel floating up from on of your worms bodies and playing a harp before sobbing, then laughing as the worm corpse suddenly gets up, resting on his (invisible) shoulder as he shakes his head in dissapproval... before having the harp pin him by the neck to the ground.
Hell, any of the success movies would count, bonus points if you get an award movie for traits like destruction (worm using several cannons), survival (worm with a kamikazi bandanna receiving a care package from a heli) and they all start the same, but end differently depending on the rank.
Try throwing a grenade towards a bundle of worms in Reloaded and they all start screaming. Not a continuous one, either, they just scream multiple times with a blank expression and in the most hilarious way ever.