A demo of MindFlex — a new consumer toy by Mattel.
A $180 toy, that allow you to move a ball in a user-generated obstacle course. The mind control the speed of a fan that lifts the ball, you use your hand to turn the obstacle course, the results is amazing. Lots of fun. http://www.mindflexgames.com/.
As far as I can tell, there are 3 sensors here, more advance sensors include 6, 12, and even more sensors to allow more control.