I can't remember for sure but I think back then it was all in the video driver wasn't it? I don't remember whether the games had to be specially coded for 3d or whether it was all done via the nvidia driver. Hmm I should take these glasses to work & chuck quake 3 on there (work pc is where my old gf2gts is).
haha, well these days, since the 8000 series of nvidia cards, the driver has had the option of being 3d, you just need to enable it in the nvidia driver, and have the correct hardware.
Hell if you don't, you can still get some cellophane and cut out some red and blue pieces, stick them to your face with tape, and then enable that style. Tried it a while back, pretty funny results. (yes there is actually a red/blue 3d effect which works, obvs not as well as the real stereoscopic).