Ingenious (and Fun!) Water Pump
In places like Africa where clean water is at a premium and girls must often spend much time carrying it from the source to their village, PlayPump works at a nearby underground source. How does it work? It’s a merry-go-round! Five minutes of kids playing on it provides a good-size bucket of water. See the YouTube video
Source: Guy Kawasaki – The Cleverest Idea I’ve Seen In Years