Average calories burned: 500
Cost per class: $16
Cost per calorie: 3.2 cents
Class time: 1 hour

A combo of Pilates, kickboxing and dance, this class packs a fat-torching punch while toning your muscles. Translation: You get the lean-muscle-building benefits of Pilates and boxing -- not to mention the abs workout of both -- plus, the cardio burn of high intensity intervals. A note: If you don't like to dance (in public, anyway), you may want to skip this. There are definitely some Zumba-esque moments.