PC World describes cell phones that charge kinetically:

. . . if you check out the ModeLabs website, you’ll see something different: three concept phones designed to capture energy from actually using the phone. (It’s the same concept as hybrid cars that use the stop-and-start of city driving to capture energy.)

The three phones are the YoYo, U-Turn . . . and Runaway, all of which work with motions associated with the type of phone.

The ModeLabs website is a handsome digital environment with lots to see. Clicking the Kiosk and then clicking the Concept phones tab activates a movie showing the YoYo phone acquiring its energy: the phone shown above around its owner’s neck is seen in the movie zipping up and down the cord that makes it a yoyo. I wonder if you get a super charge by playing ‘rock-the-baby.’

Thanks Greg