One band I was in had rehearsed up to the point of gig-readiness - we were all experienced and playing pretty standard covers. The drummer was in another band as well, so we organised a double band gig at a local pub. The drummer, singer, the guitarists, singer, and bassist from the other band, and me were all there, wondering what had happened to our guitarist. After some time (this was in the days before mobile phones) we got a message that he'd jumped in the canal and I think had been taken to hospital. He'd always been a little strange but never seemed that way inclined before. Anyroadup, we borrowed the other band's guitarists and got through the gig (the advantages of playing covers that every bugger plays).