The Gravitylight: Lighting For Developing Countries
GravityLight: lighting for the developing countries on Vimeo.
This is so cool!
"GravityLight is a revolutionary new approach to storing energy and creating illumination. It takes only 3 seconds to lift the weight which powers GravityLight, creating 30 minutes of light on its descent. For free."
And here is a "less old" link.Their second fundraising campaign has also expired, but you can still how well they did.