the rocker works on small bumps until the red bumper contacts the chainstay, then it activates the second phase of travel. Complex, but almost beautiful to watch it work.
http://www.sinisterbikes.com/index.htm
new AM frame from Sinister using "VST" (Variable Suspension Technology) for two different rear suspension travel directions. Price and final design is still in the works. Also watch for the "Poison" frameset.
http://www.sinisterbikes.com/index.htm