Although billed as a solution for developing nations often unreliable or nonexistent electrical services, we like this one for camping. Three University of Michigan engineering students have created an affordable solution for charging and lighting when electricity is unavailable. The portable solar panel can charge a phone in the same time your wall charger can, and provide light for up to eight hours. They hope to sell the device for under $20 to the developing world. I would not mind having a few of these around myself.
Cheap Portable Solar Charger and Light Source