Not a bad piece on the evolution of the backflip on wikipedia. Says in 2009 Cam Sinclair was the 3rd person ever to land a double backflip.
http://en.wikipedia.org/wiki/Freestyle_Motocross
The Backflip was once considered the "holy grail of FMX". It was a trick that most riders considered impossible and was considered more appropriate in video games than in real life. Speculation of the possibility began with the Motocross film "Children of a Metal God" featuring riders attempting the trick into water off a modified ramp. Also it had been done many times on BMX bikes, and FMX riders were using tricks from BMX riders, such as when Travis Pastrana performed an Indian Air, originally from TJ Lavin, a BMXer.
In 1993, Bob Kohl was the first ever person to perform the backflip on a motocross bike. The bike was an 1993 Honda Cr80. He was a professional BMX rider who had performed the trick regularly on a bicycle. He continued to exhibit the trick until a crash in 1995 left him with serious injuries.
In 2000, Carey Hart attempted the first ever backflip on a full size motocross bike off a modified dirt landing ramp at the Gravity Games 2000. The landing was less than perfect with Carey crashing immediately after. Speculation in the motocross community following, with many people claiming he completed the trick and others claiming to have attempted it.
