Water
Not sure if its funnyness is entirely intentional. It’s from that era in the 1980s (after Life of Brian and before Four Weddings) when the British film industry was pretty much funded by George Harrison.
It’s got an ‘interesting’ ensemble cast featuring Michael Caine, Billy Connolly, Fulton Mackay, Leonard Rossiter (I think it might have been his final performance on film), Ruby Wax and, er, Ringo Starr (playing himself).
Billy Connolly plays a half-Caribbean revolutionary who only communicates via the medium of reggae, sung in a Scottish accent. Can’t figure out why this one didn’t set the box office ablaze.