yeah, there's been videos on youtube/google for a few years with this type of thing. Apparently it's pretty big in eastern europe.
this video is pretty cool: http://www.youtube.com/watch?v=3KSr1pozm6Y
I like the overall concept of it, though. Be kind of neat to be able to build a more controlled 'course' for it.
Just searching on youtube for parkour yields a lot of videos.