I DJ electronic music (mostly trance type stuff) so I work with "rave" promoters. I put rave in quotes because the stereotype (perpetuated by people being idiots I will admit) doesn't apply to the shows I'm involved with. There is a big emphasis on safety and responsiblilty, although sadly these two things rarely make a promoter money as this requires the show to be properly permitted and usually a security company is hired (not cheap at all!)

200 is about the average attendence for a party although the event I'm hitting this weekend has an expected attendence of over 500 people (paying 20-40 dollars a piece, depending on when they got their ticket) and the promoter has a good shot at not breaking even. Again though, its about having a good and safe time, not about the money.

Sorry about getting off topic