Potenco

The Potenco PCG1 pull-cord generator creates electricity for portable gadgets with far greater efficiency than hand-cranked devices. The PCG1 is the geek-chic version of a generator for the developing world. It weighs 14 ounces, has both an internal NiMh battery and a mini-USB output jack and can convert 2 minutes of effort into 40 minutes of cellphone talk time.

Watch video demo here

and check this: The future is bright!