If you can stop watching this once you start, you're a stronger viewer than I. Simply amazing.
Here's the info straight from the YouTube posting:
Filmed over the period of a few months in and around Edinburgh by Dave Sowerby, this video of Inspired Bicycles team rider Danny MacAskill features probably the best collection of street/street trials riding ever seen. There's some huge riding, but also some of the most technically difficult and imaginative lines you will ever see. Without a doubt, this video pushes the envelope of what is perceived as possible on a trials bike.
I keep hearing Chevy Chase saying, "Be the [bike] Danny."