BMX racing is pretty straightforward. It's flat-out racing, every man or woman for himself trying to be the fastest around the course. Riders start from a high drop and then attempt to be the fastest to negotiate their way around tracks featuring funky jumps, banked corners and other obstacles.
Eight riders compete in each heat of the Olympic BMX races, which are held on a track usually around a quarter-mile (350-370 meters) long. That means a good rider will take only about thirty seconds to get through the course. Here is a 3-D look at the Beijing track.
Four initial heats are run with the starting field of 32 male riders (16 riders in the women's event), and the top four finishers in each heat then move up to the next level. This means there are four total rounds in the process to determine who'll be standing on the medalist podium when the dust settles.