Fresh on the heels of another evening conducting at band, some of it in 5/4 time and 3/4-2/2-4/4 time (a bit of a mind mashing experience that), I wondered what the most unusual time signatures were.
I came across these.
Here Comes The Sun by The Beatles. The guitar part of the bridge can be transcribed like this:

Prelude no. 15 from The Well-Tempered Clavier by Johann Sebastian Bach: 24/16

Crystalline by Björk: partially in 17/8

I should thank my lucky stars…