It's essentially an elaborate spin on one-on-on dodge ball with a Tron aesthetic. You have a shield that you can block your opponents ball with, but you can't block your own (yes, there are two balls in play at all times.) It's a pretty straightforward concept, and given that it uses motion controls it actually makes you move---almost like a real sport. Using VR to get in shape is one of those lofty Utopian ideals, but Sparc sounds like it could do just that.