In reply to mux:
Black Eyed Peas, supporting Macy Gray back in, ooh, 2000 or so. In between buying tickets and the actual gig, Macy Gray had become really popular amongst the sort of people who will buy tickets for a gig just so that they can hear the one famous single they actually know. BEP went on for about five hours, making the sort of noise you'd more commonly expect from the Vauxhall Nova owner's club. It was really, truly, abysmally dire, and even the traditional resort of decamping to a bar was ruled out by the effect of the bass rumble on one's lower bowel.
Then Macy Gray came on and everyone breathed a sigh of relief, right up until the point when she opened her mouth and let off a stream of invective. Cue a few thousand sharp intakes of breath and simultaneous clapping of hands over children's ears. I didn't hear very much of the actual gig as I was too busy laughing at the woman behind me. "This is, is, well, it's filthy. I've never heard such smut..." Sneaking a look behind me, I then discovered her hands moving like Marcel Marceau as she frantically tried to stop her daughter from either seeing or hearing Macy Gray do something very unclassy with a microphone stand.
Actually, on second thoughts it might have been one of the best gigs I've been to, even if the acts were total pish...