Using 1.11.05d, this problem is happening on all sites and all games. The tables initially freeze up, then they all go completely black, with table sounds still going on. It appears to happen randomly. I'm usually only playing 1 site (stars), and it seems like it's happening ~ once/20 minutes on average or thereabouts.
My computer is a 3-month old Samsung R780, fully specced - 4gig of ram, i5 2.4GHz, windows 7, using a 24" external output via HDMI.