Our roadie forgot to pick up the singer on one gig.
He arrived at the gig with the PA and no front man. We were bass, drums and guitar, and had to scrape a couple of set lists together in 20 mins. We all sang a couple of songs (even me) and played a few instrumentals, then we asked if anyone in the audience would like to do a number. A guy in a suit got up and sang some rock and roll in the style of Johnny Rotten on speed. This was 5 years before JR.
We also had a guy who was transitioning into a woman! He got up and did a strip to us playing Green Onions. He got everything out, meat and two veg and a pair of boobs!! We made it through the night and even got an encore! I wish someone had recorded it.