I had this idea while reading Clean Coder.
Back in my school days, I, too, was engaged in a fighting sport (karate). So in case you haven't heard the term before: A kata is an exercise in which you show only one part of an imaginary fight. The steps are all predefined. The goal is not to show off how good you are, but instead perfect your skills.
By now, I couldn't make time to pick it up again.
But what about exercising them at home in the meantime?
The VR app would allow me to rotate and zoom around a rig doll doing katas. I would be able to pick from a list of different ones.
In case I want to exercise on my own, the very minimum would be an audio output which counts in intervals. Bonus if technology is far enough to track your movements and check it against the predefined steps of the kata.