Kris Holm is a unicyclist who used to ride some pretty gnarly trails (yes, on the unicycle). You can see some of this on youtube. Looks like he has gotten more into more of a trials/street form of riding.
The next video is sort of a promo for a Contour video camera. I love this vid though. It just gets me stoked to go out and ride. Mike Kinrade is know for his big mountain riding style and it shows here. Looks like he was just out having a great time with his buddies which is my favourite reason to go mountain biking.