6. Spinal Tap - (S3 E22 "The Otto Show")
They don't know what town they are in, the drummer explodes, the set ends in disaster. So, typical Tap. This was the capper to the insanity that was Season 3, in which The Simpsons really exploded into the mainstream and it involved one of the first meta-instances in cartoonism as Harry Shearer, as all should know is the voice of at least 10 characters on the show crossed into his other job. He was also Derek Smalls in Spinal Tap so for this episode not only was he a regular cast member but he was also a guest star. It was a nice nod to the absurdity of Spinal Tap and introduced another generation to a yet-another band they never heard of and to those that did know of Spinal Tap, it was a good instance of The Simpson straddling that fine line between stupid and clever.