Giving you a reason to ride a bike besides "I care about the environment!" or "My license's been revoked!", the Siva Cycle Atom's a small, lightweight & water-resistant generator that harnesses the energy produced from cruising around to juice up virtually anything that can be charged via USB
Consisting of two interconnected pieces, (one that converts the motion of the spinning wheels into energy and a detachable battery pack), it provides two charging options. You can plug in and power up on the go (if you're comfortable steadying a pricey gizmo while in motion), or ride around for a while recharging the battery pack and remove it for use as a backup power source.