3D is in games already.
The glasses that i got automatically convert Open GL, and Direct 3D with their drivers. The technology has been around for a while but it is getting better with each new model. I was a bit skeptical about how they would work but they are as clear as looking at a monitor normally.
The way polarized lenses work (i think) is that two images are projected from a screen and each lens is polarized to only pick up on one of the images. I think they are a bit like Shutter glasses except less bulky.