High Tide Associates has just released the RollerGen, a human-powered electrical generator that attaches to your bike. Unlike other commercially available pedal-powered generators, it allows you to charge a battery pack for any USB-compatible consumer electronic device while you ride.

The complete RollerGen package includes a rack that fits most conventional bikes, a RollerGen Dyno, which generates current in a friction-drive arrangement with your rear wheel, and a removable battery pack that can be used to charge a variety of devices, including cell phones and MP3 players. High Tide Associates estimates an average cyclist can easily direct 30 watts of power to the RollerGen while riding.