Back in the early 80s singer in my band was unavailable for a gig I really wanted to play, so slung together a band with minimal rehearsal, first up of 3 bands. Due to very mixed backgrounds material was a problem and we finished with a version of Freebird with the vocal section arranged for male/female folk duet backed with concertina before the (competent) guitar players got to cut loose at rather less length than the original. To my complete surprise audience calls out for more and I ask "are you serious?".