I failed one a little while back, well I assume I failed, as they never had the courtesy to let me know.
I think I failed due to not being able to impress with a jazzy sort of improvisation. The weird thing was, that the audition was supposedly for a soul/function band I had learnt the six songs asked for, in less than twenty four hours from first contacting them, to turning up for the audition.
I actually ended up not really wanting the job, as I suspected they were going to be one of those "get together every week and rehearse for ever" type bands. Even so, it still smarts a bit to be rejected.