Slow motion fireball tennis. You won't see an epic match between Federer and  Nadal playing this one though.
This is what The Slow Mo Guys did with their high-speed Phantom Flex camera.

It's perhaps one of the dumbest ideas, should you get hurt playing this. But when captured at 2,500 fps, it's simply art. Can't say this game won't ever come to the mainstream now though.[The Slow Mo Guys]