The Rutles: The Rutles (1978)
All You Need Is Cash was a 1978 comedy tv special framed as a faux documentary about The Rutles, highlighted by original music and videos.
I haven't watched it in years; from what I recall, it was more silly than funny, but an amusing treat for Beatles fans. It was written by and starred Eric Idle of Monty Python, with cameos from Mick Jagger and Paul Simon and a large chunk of the original SNL cast. The music was composed and performed by Neil Innes of the Bonzo Dog Band. And the soundtrack album is freakin' wonderful.
Innes brilliantly captures each era of the Beatles, with a variety of songs that serve either as identifiable parodies of actual songs or tunes that simply mimic the style of a Beatles album without hewing to a particular song from the Beatles catalog. With few exceptions, the songs don't aim to mock the originals; while sometimes lightly humorous, they are for the most part done straight, like covers of songs the Beatles might have written if they were just a little less lyrically astute and a lot goofier.
Sometimes the homage is pretty obvious -- "Hold My Hand" for "I Want To Hold Your Hand" combined with "She Loves You"), "Ouch!" instead of "Help!," "Piggy In The Middle" for "I Am The Walrus," and "Get Up And Go" for "Get Back." But you've also got songs like "Cheese and Onions," a generically psychedelic pop song from the faux Yellow Submarine Sandwich cartoon, more Beatles stylistic pastiches than obvious song rewrites.
But the remarkable thing is how great the thing is, start to finish. If you lived in a world without the Beatles (hey, what an interesting idea for a movie...) and someone told you this was a career overview of some classic rock band from the 60s, I really think it would be thoroughly enjoyable, even great, without knowing the references. Getting those references just adds another layer of enjoyment.
Here's "Cheese and Onions":