Wakko and Scratchnsniff:"W: Knock-knock. Dr: Who's there? W: Max. Dr: Max who? W: Max wants to come in an' go crazy! Dr: See, that's not funny because it's not really a joke. W: It is if you know Max. Dr: But I DON'T know Max. W: If you did you'd be laughin'!
-Wakko and Scratchnsniff"