I'm not sure if there's a sure fire way to top that one skit above, but that was from Portal 1. Portal 2 has some possibilities since there's more dialogue (Not from Chell, obviously) but I like the idea of the simulated audience/telling a joke test. Brilliant homage to the first moments of the game.
But if all else fails, yeah implement the music somehow.
Red Sniper (TF2)
Wreck it Ralph (Wreck it Ralph)
Tommy Vercetti (GTA Vice City)
Ash Williams (Evil Dead)
Wolverine (Marvel Comics)
Rex Power Colt (Far Cry 3 Blood Dragon)
Plans for 2014:
Turbo (Wreck it Ralph)
Soldier and Medic (TF2)
Bad Cop (The Lego Movie)
Sonny Crockett Batman (Miami Vice/Batman mashup)
Cheese Sandwich (MLP)
Next con: Momocon