From her perch on a raised stage, Jamee sways her hips and throws her hands up in the air. An entire room of smiling students follows suit, dancing up a storm as international beats blast through the speakers. So goes a typical day at Zumba with Jamee, where classes incorporate easy-to-follow dance routines that burn calories, tone muscles, and improve flexibility. Jamee also holds special Zumba Kids sessions and birthday parties that take youngsters through fun dance routines while they lift heavy cakes above their heads.