Same problem here with a clean Ubuntu 12.04 LTS 64bit, and tested with latest 295.53 drivers.
G80 [Quadro FX 4600] card.
I can let it crash quickly with watching the Travel Journal demo video at http://www.adobe.com/devnet/flash/ar...ith-flash.html
Most of the times it crashed at the first play within a few seconds, sometimes I need a second play, and then it will crash.
But as others told the system crashed randomly (not when idle).