According to some very vague articles I read online today (Livestrong.com, I'm looking in your direction), Bikram yoga is up there next to Zumba in the ability to burn 1000 CALORIES PER HOUR!!! The emphasis is mine, and used in an entirely facetious fashion.
Really, the number of calories burned depends entirely on the individual. Bigger people burn more calories for the same exercise than a tiny person. Unless you are monitored, there's no way to really determine exactly how many calories you burn during exercise. One can only estimate.
My favorite exercise for seriously burning the maximum calories per hour? Rowing. Either for real (if you can) or on a machine. It uses muscles throughout your entire body, from head to toe, and is incredibly aerobic. Try doing fast-paced squats while at the same time lifting a weight from the ground up to your chin for two solid minutes. Now multiply that by 30. Yeah, it's hard core. Now do it while running around like a soccer player. (Naw, I'm just kidding about that.)
Anyway, I think the room was extra hot during yoga last night because the sweat was coming off me in disgusting, salty waterfalls. Strange thing was that I was also completely relaxed most of the time. I'm hoping my leg muscles catch up to this new level of exertion quickly, because I'm getting tired of being this sore all the time. Or I need to find a nice massage therapist cabana boy to work on me every evening.