This guy is amazing - he builds wind powered sculptures that can walk and run. Watch this right the way through!
http://www.youtube.com/watch?v=FMqftVhOuTw
theyd struggle to do that in robotics.. nevermind with some twigs, twine & wind
The Mechanism
http://www.youtube.com/watch?v=CufN43By79s&feature=related
And on TED.com -- http://www.ted.com/index.php/talks/view/id/162