Creative Wii interfaces
I like new computer interfaces. It’s amazing that the Wii is allowing many people to make their own creative hacks that are actually quite powerful.
Wii finger tracking
I can imagine that this principle one day would also allow you to make/design physical objects just by waving your hands. At least it allows for nice augmented reality and human interfaces for CAD.
There’s also the Wii nunchuck interface to arduino: