I saw this recently. The road they're on is in the Berkeley hills. Maybe you can already tell by the speeds they're carrying but that hill is steep. I used to live at the base of it and did a fair amount of training rides up it -- in granny gear.
What they're doing is insane. One pebble at the wrong time and you're toast.
That was the most awsome thing I've seen all week!!! Without the insane, there would be no entertainment, thus a boring world and no sportbikes. Thank god for the insane!!!