Season 5, Episode 1
During a family trip to the Springfield Swap Meet, Bart stumbles across an old record which features Homer on the front cover. When he asks his father to explain this, Homer tells the story of how he, along with Apu, Principal Skinner and Chief Wiggum formed the short-lived The Be Sharps - a recording outfit which dumped Wiggum and replaced him with Barney back in the mid-1980s.
Ex-Beatle George Harrison guest stars and there are several subtle references to the Fab Four: from the album cover to the final scene with the guys playing their last gig on the roof of Moe's Cavern (note the blatant spelling change from Tavern).
See here for more details.
Notes & Screenshots: Lord Heath