http://www.youtube.com/watch?v=Jd3-eiid-Uw

This is some pretty neat stuff. Using the Wii-mote and the Sensor bar backwards to get a different perspective on a 3D gaming enviroment.

Using the infrared camera in the Wii remote and a head mounted sensor bar (two IR LEDs), you can accurately track the location of your head and render view dependent images on the screen. This effectively transforms your display into a portal to a virtual environment. The display properly reacts to head and body movement as if it were a real window creating a realistic illusion of depth and space.
There is a lot more on the guys website:
http://www.cs.cmu.edu/~johnny/projects/wii/