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)
Torgo (Manos: The Hands of Fate)
Cosplay in progress:
Rex "Power" Colt (Far Cry 3: Blood Dragon) (10%)
MacGyver (MacGyver) (80%)
Fix it Felix Jr. (Wreck it Ralph) (80%)
Ken Rosenberg (GTA Vice City) (20%)
Turbo (Wreck it Ralph)
Dr. Forrester (MST3K)
Convincing John (Fraggle Rock)