I watched the first one yesterday afternoon and was still marveling about the downhill skiing without skis, and then I just watched the second one that Elkhunter posted. I was about sick just watching it. Nuts would be an understatement. Incredible. I think he could almost beat a mountain goat up the mountain.
I marvel at the dedication, discipline and sacrifice it takes to reach such a peak of physical ability as these two guys did, the human body is capable of so much and most of us just barely scratch the surface.
Call me a bit of a pessimist, but the credits of the first video give the stats on the run: 3.2 miles, 2300' gain/loss and 61 minutes best time (~18 min pace). The guy is a stellar runner, but the video is deceptive with having to leap frog the camera (he had lots of rest between bursts of running) and a little low angle work on the rock face.
Don't get me wrong, he's a fast dude in awesome shape (especially compared to most of us), but he doesn't run like that when it's just him.
Maybe I just look for reasons not to believe videos in the internet.