Theo Jansen's Strandbeests
These are amazing! Theo Jansen is a Dutch artist who creates lifelike kinetic sculptures called 'Strandbeests' (Beach Creatures) that move on their own. How come I've never heard of him before?
You can hear and see Jansen and his work on the always informative and educational TED website. There's a good film on YouTube as well, plus an article in wikipedia. A fascinating artist, scientist and engineer all in one!
(Thanks to Erika for this!)