Golden_Eagle said: 

Another thing for Med. The hula hoop. 

It works the core, and if she does it enough she'll get a 6 pack, and even better if she's curvy cause it'll really slim out the torso.

This might be sarcasm on your part, but hula hoop enthusiasts do tend to be in pretty amazing shape. It's core work, which is the center for all other movements, and I've seen some theater types take to it well for working on routines with it.