If you have access to a gym and wights I definetly sugest squats and cleans, both half and full. Make sure you get properly trained in good technique for both because once you start exercising with weight these two lifts can do serious damage to your back and knees if not performed properly. They also require a spotter to help you if you lose control of the witghts while training.
The crunches develop the slow powerful strength in your legs while the cleans develop the quick burst of force in your legs and upper body.
If you want something a bit less typical, a partnering dance class might be fun as well. An hour of lifting and throwing a fellow dancer around can be quite a workout for your whole body.
Intense Pilatis works well too, and you can practice that for free at home. Just learn some moves from a video or book (you can find one at the library) and do them on your own at home with some good music every night. I like pilatis myself because I can modify them easily when I get boared with the move and find new and fun ways to workout muscles I never knew I had.
This should get you started.