Slightly related: South Africa's Roundabout has devised a way to harness the energy generated by kids playing (ingenious in itself), as they spin on an outdoor

Slightly related: South Africa's Roundabout has devised a way to harness the energy generated by kids playing (ingenious in itself), as they spin on an outdoor merry-go-round http://www.worldchanging.com/archives/000446.html http://www.worldchanging.com/archives/000446.html