Well, I used to be able to do this real loud, deep, evil laugh. It's not quite as long anymore, takes a lot of breath, but I still can. I can roll my tongue. I'm not sure if people can usually do this or not, but I crack my fingers. Not like the knuckle part, can't do that. But the middle join on the finger. That includes my thumbs, but not my pinkies or the ones right next to them. I can sometimes crack my big toes...and other various parts. Ummm I think that's about it lol.

Edit: Oh, and I think my elbows are...semi-double-jointed. You know how you put them out, and their straight? Well mine go back a the other way a tad.