This is a great demonstration of using Kinect to operate a robot. This would be great for teaching people repetitive gross motor memory skills like I was doing at CRA. Having the ability to teach people how to enter a room and clear it requires repetitive actions and peripheral awareness. It would be interesting to do this using the Kinect. The other things it could be used for when the tracking improves is for body positioning when practicing for a sport. Imagine being able to track the pitching arm and being able to see ideally where your rotation should be compared to your actual position. Then like a video game you could keep pitching and adjusting to fit the ideal model.
Secret of Success: Obsession
You need to love what you do so much that you think about it all the time and do it all the time. That is the key differentiator. You need talent and intelligence, but it has to be coupled with obsession (or love as Malcolm says).