Zumba!

I would say 500 to 1000 depending on the intensity

http://www.zumbacalories.com/

Heart Rate Monitor is the best way to know.

depends on the intensity with which you commit to the movements. when i first went ,i barely burned 300 cals in an hour b/c i was just busy trying to learn the movements. As i went back more often and grew more confident in the sequences i could put more "umph" into it and burned more calories, usually between 400-450 in an hour. I can generally burn over 600 cals on an elliptical in an hour but the reason i started zumba is b/c after all those repetitive movements that come from doing cardio like running, elliptical, cycling, roller skating - i needed something that would give my legs and hips and core more variety of movement. it helped prevent stiffness and overtraining from the other activities, so even though i burned less calories, i really do believe it was overall more beneficial to do zumba versus, say, running. give it a try and have fun