Nike recently challenged 78 artists to remix and adapt the function of Nike shoes. Nick Marsh, one of the contestants, took a pair of Air Maxes and imported the internals of a Wii Balance Board to turn his shoes into controllers.
He placed the Balance Board sensors in the soles of the shoes and re-jiggered some wires to turn Air Maxes into a working Balance Board. According to Nick, the shoes work like this:
The user simply puts on the shoes, turns on the balance board/shoes (nike-wiis) and then plays as normal, except it's not a normal way to play. As you are now physically attached the to the board, the actions have changed, you can no longer simply step off, so you must lift your foot and stand on one leg or sit down when no pressure is required, making for an altogether interestingly different experience.See Video on Nike Shoes Hacked for Wii Balance Board
I think this would have a lot of implications for Physical therapy for Gait, Posture, and Vestibular Rehabilitation among other things. You could really hone your sports skills with the Wii as good balance is the foundation for many sports. When you look at what top sports coaches look out for, they look at vision, and balance. Balance drives good form whether it is a golf swing or a hockey swing.