I've read one article recently... it was about Manchester's Center Nanotechnology where scientists explore gecko, it is such lizard that can climb for almost any surface. So scientists found out that geckos have row of very small hairs at its foot every hair approximately 200nm. Due to capillary attraction it can creeps up to wet surfaces and van der Waals bondings keep it on dry ones. Every hair sticks surface with 0.00000001N! Because great among of hairs the force is increased. Team from Manchester continues researches and tries to replicate gecko's nano-hairs and they don't except that "gecko's foot" could be made quite easy. Well I like rock climbing and I would be glad to test such devices… right!!! :)