I'm not sure if this is craft, meditation, performance or art. Either way, this interview with Adrian Gray, stone balancer and photographer, is well worth a look. It was filmed at the Glastonbury Festival of Contemporary Performing Arts 2007, with Billy Bragg performing in the background.
Another rock balancer, Bill Dan, maintains a blog "The Rocker : World wide phenomenon" featuring photos of balanced stones from around the world.
Not to be outdone, nature has already provided us with examples of balanced or rocking stones, such as the Logan Stones of Dartmoor, Balance Rock at Lanesborough and Balanced Rock in Arches National Park.