quote from Tiltedscreen.com
"Are you one of the millions that watched the super bowl with those cool 3d glasses? Do you still have those 3d glasses sitting around and now don't know what do with them? Well you're in luck, In the Left 4 dead mod scene a developer by the name of Dragon has release a hack that allows users to play left 4 dead in wonderful 3d. The set up includes use of the GeForce 3D Vision drivers, and a registry hack. Not to much work for such a large pay off."