Mine is The Seventh Seal satire, where Yakko? Plays checkers with Death for his very soul. Not only do they skewer a really boring and depressing existential film, but I love their crowing: "Can we call you Dadoo?" to Death. We used to call my friend's dad 'Daddoo' because my nephew watched the show and decided to call him that. We thought it was hilarious. Love this show, but this is my all time favorite skit.
Obey My Dog! -Mugatu