That's some biker on top of Moscone West, filming a commercial for Google's New Terminator Glasses, so says the uploader of this video:
Turns out it was for Google. They were doing a demo of project glass. Pretty awesome!
While the jump itself looks pretty lame embedded above, if you bump up the quality and full screen it, you can see the biker do a 360 and not the ramp doesn't reach the top of the roof--he's got some 3-4 feet to clear--which kinda makes it cooler. Also, according to the uploader, "they had some people fly in by parachute too"--which definitely makes it cooler.