"We have developed a collection of mobile phone games that incorporate physical gesture interactions. Users interact with the game by physically moving the phone in free space. For example, in Pong, a user moves the phone left and right to control the paddle. The games do not rely on special motion sensors. Instead, they use the mobile phone's camera as the 'motion detector.' By using computer vision techniques like motion blur detection and optical flow it is possible to detect up to 6 degrees of freedom."
Now this is pretty clever and most definitely falls under the W?BIC! heading. It's one of several projects carried out by Georgia Tech Mobile Lab, but could easily be commercialised. Think of the fun of being on a bus full of kids all playing gesture based games. :helpme: However, games like these could help under-active folks to get fit. I know someone that bought Dance Dance Revolution for that purpose. As Engadet say, just imagine what kind of gestures you'll need to play Doom on your Pocket PC. ;-)