A genre of photography I have wanted to add to my portfolio for some time now is Gigs. I finally got an opportunity to do some of this type of photography last year
Limited time to shoot (normally 4 songs and you are out of there). Not every venue has a photographers pit so you are in with the crowd getting shoved around, and then the lighting conditions. Flashing lights, different colours coming from different directions and a lot of the time from behind the acts.
All this combines to make it without a doubt one of the most challenging types of photography I have ever encountered - but one of the most rewarding when you get an image you are proud of.