I played what was supposed to be just another lunch-time residency at a bar in London. What we didn't know was the owner had decided to tackle falling revenues during the day by hiring a stripper. Given that we were setting up our gear when he explained this, refusing to play was hardly an option. And hey - we were young, foolish and getting paid.
No words can describe the embarrassment of being a band on stage, facing an audience of men who are looking at the woman in front of you who is the real center of their attention. You don't want to make eye contact with them, you don't want to look at her... Meanwhile the sunlight is streaming through the windows and there is a lovely view across the Thames.
So, just as if we were on a crowded train, we all turned our eyes to the windows. And that's why we played the most awful, random stuff that day!
We still got paid, but we never went back. So maybe not 'unusual' but it was a very uncomfortable, and unexpected experience.