FMX is amazing, I am sure the guys who do it are meiing about with the laws of physics somehow. It must be witchcraft or something.
If you like FMX try and get hold of the TV show Nitro Circus, it's basically Travis Pestrana (FMX legend) and his mates messing about. Bit like Jackass on bikes.
Best guy on it is Street Bike Tommy, so called because of this.
http://www.youtube.com/watch?v=pysnqokS6KU