Kinetic energy provided by human muscles is a great source of clean, renewable energy, but one that we don’t often exploit as much as we could. K-TOR’s Power Box is a pedal-powered generator equipped with a regular power outlet that lets you charge low-power devices (up to 20W) with nothing but the movement of your legs.

The power box weighs just 4 pounds and folds up into a box small enough to fit into a backpack, making it easily portable. You can use it at home or work, or take it camping to ensure you’ll always have a way to charge your phone and iPod. Any charger with a wall plug can plug right into the Power Box.

Just as exciting as the always-available energy is the potential fitness benefit to be gained from the Power Box. Studies have indicated that people who use pedal devices like this under their desks at work can burn an average of 500 extra calories a day. The device doesn’t produce a lot of energy, but it will give you enough to charge your Nintendo DS for a little lunch break gaming time.