The Beatles' cartoon series
Ever see The Beatles' cartoon series? I didn't, but have recently discovered it via a number of episodes lurking on YouTube.
Made for American TV and screened from '65 until '69, they were shorts - and pretty awful, but at the same time very watchable (for all the wrong reasons). The voices aren't by the Beatles - they were even "Americanised" for the US market. And the scripts are just vehicles for songs - for an example of this, check out the episode below. It's called "Paperback Writer", with the story seeing the lads asked to write the band's story...for a paperback.
Yes, it's that obvious.