Crazy Vertical Indoor Racetrack Thing

Is it just me or does this look insane?

No helmets or padding. Fixed gears; no brakes (click the image for a larger view). Imagine if one would fall (they probably all would). Look at the guy in the rear riding high on the rim. How, I wonder, did they begin (to get enough centrifugal force to get vertical), and more importantly, how did they stop gracefully.