Not last night but the night before...
At 8 hours' notice, played with Shaun Buswell on the first night of his latest Orchestra Challenge tour. He books a string of venues, prints out sheet music of 17 songs for 20 orchestral instruments, tries to recruit random players during the daytime, and everyone pitches up and plays form the dots in the evening.
As it happened, there were no orchestral instruments, just Shaun on guitar and vocals, a chap called Chris on keyboards, and me on bass (playing from the DB score). The audience (who mainly don't know the songs) call out numbers (e.g. '3') and the band play the corresponding songs. It was the complete opposite of the more usual scenario where you practice and rehearse with a view to getting it right; instead, it all just happens, and it was mainly pretty good.
I very much enjoyed it, and didn't even mind the very drunk man treating us to 'interpretive dance' at the front. He enjoyed it too btw.