What exactly is a rave, anyway? I've heard all sorts of things about them, but I've never heard from anyone who's actually been to one. So I'm pretty sure all I've heard is rumor, wild exaggeration, fear and speculation, just like when antis talk about assault weapons.
So what really goes on at a rave?
Mostly just adults-at-play, but it depends on the crowd and what you're going to. Electronic music has kinda turned into pop as of late, so people throwing proper raves are basically reaching out to an older (and in that I mean the 30-40 year old range) crowd by comparison to most club or party goers. Every major area is going to have different electronic music events, whether or not they are raves or shows is another story.
As for the fear and speculation, there are drugs present in any aspect of nightlife. If you go to a local bar, someone is assuredly consuming something illegal. Crazy stuff doesn't really happen at anything I find myself at, even if people are intoxicated on whatever. IMO, more power to 'em, and I wish it was all regulated and creating jobs as opposed to funneling money into the hands of generally horrible people. At shows (like proper concerts, but with electronic music), you'll probably see more irresponsibility and patent abuse of drugs (including alcohol) than a "rave" these days.
Even at events where there one can find excessive indulgence, the concepts of raving generally preclude any kind of violent crime. You also find a lot of specialized professionals at raves now, and there are great business and interpersonal networking opportunities in such libertine atmospheres where people don't act erratic for the sake of it. Weird expression is common (example, I usually dress up in a suit plus bracelets with a rainbow prism patterned top hat worthy of the Mad Hatter), but bizarre, violent, or intimidating behavior is extraordinarily rare.