If you want to try something a little bit different but a lot of fun you could go out and buy a Nintendo Wii
It might sound silly at first but it keeps you moving and it can get your heart rate up. The system comes included with a Sports disc that has various games like tennis, boxing, baseball, golf, and bowling. They even have a workout version of the games where they keep you moving to get your heart rate up.
I played the boxing game on there a couple times and it really felt like a good work out. I'd definitely recommend it if you were looking for something different.