Yellow Submarine (1968)

Continuity mistake: During the song "Hey Bulldog," before the song starts the dogs are on a leash barking. When the song starts and the dogs stop barking, the leash disappears.

Ringo: Hey, I wonder what'll happen if I pull this lever.
Old Fred: Oh, you mustn't do that now.
Ringo: Can't help it. I'm a born "Liver-pooler."

Trivia: The original Beatles did not voice themselves in the film. They only showed up at the end and they sing the songs.