I may have said this before, but the best thing one can do with regards to lighting in nightclubs and concerts is to learn the basics of intelligent lighting as well as learn how to count beats and measures in songs. With dance music this is easy. After awhile, you know when the breakdown is going to hit even before the DJ does. Since most DJs do not have a musical education after all.
Though you can throw all that out the window if the club has no light tech or lights to begin with. In that case, improvise. Bring gels, bounce off of walls, and so on. Candles and practical (i.e. the architectural lighting) become your best friends. Live dangerously and shoot at 3200. Don't be afraid of a little noise. Your camera does not have a Peltier cooler (unless you're a mad scientist) and 3200 looking like 100 is about four years away. That noise is useful and can be your friend. I doubt the guy who got the headshot photo of Osama (and you know someone was there) was fussing over the ISO. Treat club shooting as an offshoot of photojournalism. You do what you can, but sometimes you have to deal with what is there. If the DJs rider says 'no flash', well, those are the breaks.
But, if you are lucky, the club/concert hall has a fairly competent tech and usually he or she is bored at a DJ-driven show. There's no specials, solos, or anything, except for maybe some dancers and switching the video loops. Obviously with the top tier guys like Tiësto, Deadmau5, and so on, there's a full-blown production, but for the most part, the tech is just hitting cues, and will be more than happy to set something up for you just to break the routine. And if it's a full blown production usually the lighting is photo-friendly anyways. Think rock concert.
Speaking the "language" helps. Walk around, get the brand names and types on the fixtures. Common brands include Martin, Highend, (yes, spelled as one word), Robé, Elation, Clay Paky, ETC, and so on. LEDs are typically sourced from Anolis or Element Labs. The round strobes are "Dataflash" and the rectangular blinders are Martin Atomics. The round "cans" are just that, PAR Cans. Google those terms for specifics.
And bring booze. Techs love booze, and email them a few shots for their lighting portfolio. You'll get it back in spades. I'm usually anti-freebie but if someone's working hard with little to show for it, I'll sympathize.
After awhile, you'll get some great ambient shots and you'll split off from the typical Gary Fong-sporting shooter in today's venues. Nothing against the Fong, I suppose I'd use one if I used my flash more, but I see a lot of guys who buy it thinking it's a magic lamp of some sort. Good for Gary though. I wish I thought of that.
