Hey Bulldog (1969)

As funky a tune as the Fab Four ever laid down – though Lennon, who wrote it, said “It’s a good-sounding record that means nothing.” Days away from their trip to India, the band were in good spirits at Abbey Road being filmed for a promotional film for Lady Madonna, and decided they would record the extra song needed to complete the Yellow Submarine soundtrack. Like I Am The Walrus, Lennon finds inspiration in gibberish (“Some kind of solitude is measured out in you/You think you know me, but you haven't got a clue”), with the playfulness offset by an aggressive menacing riff – Lennon’s raising, stamping piano, George Harrison’s screaming guitar and McCartney’s bassline running through a fuzzbox – not to mention Starr’s shuffling off-beat drums. The song was originally called Hey Bullfrog, but just before the recording McCartney had played drums on a Paul Jones song called The Dog Presides, which featured barking sound effects. While sharing the mike on vocals, McCartney and Lennon ended up making dog noises, and the song title became Hey Bulldog. Nowadays the song has found cult popularity, but at the time it was cut out of the Yellow Submarine film when released outside of the UK.

You Know My Name (Look Up The Number) (1970)

Released as the B-side of Let It Be, this was The Beatles at their most gleefully avant garde, and sounding nothing like they had done before. The multi-part song features a strange mixture of styles: shuffling from ska to cabaret to vaudeville. Journalist Tim Sommer argues that the song is one of their most important, as it acts as a “Rosetta Stone” for the group. “You Know My Name provides a fairly naked unveiling of who the Beatles admired, where they were coming from, and, perhaps, where they hoped to go,” he says. Once you get past the cod-ska section, the song is a straight-up homage to two famously eccentric British acts: The Bonzo Dog Doo-Dah Band and The Goons. McCartney admired and worked with The Bonzo Dog Doo-Dah Band; he asked them to appear in the Magical Mystery Tour film and perform their song Death Cab For Cutie (from which the American alternative band would later get their name). The Goon Show, which aired on BBC Radio from 1951 to 1960, revolutionised comedy with absurdist scenes and characters that Lennon and McCartney clearly imitate in the song. Somewhat unexpectedly, McCartney told Mark Lewisohn in 1988 that this was his favourite song, “just because it’s so insane”.

If you liked this story, sign up for the weekly bbc.com features newsletter, called The Essential List. A handpicked selection of stories from BBC Music, Culture, Capital, Future and Travel, delivered to your inbox every Friday.