Redbull Romaniacs..

[Tmall]

This race looks insane! The nitro circus guys give it a go.

http://www.nitrocircus.com/videos/0-Nitro_Circus___Redbull_Romaniacs-104.html

[jtemple]

I've seen one of their DVDs. It's a pretty insane race. I'd love to try it!