If you get IZ3D you can play N64 (and most other polygonal games for that matter) on PC in cross-eyed 3D. You have to adjust the effect and that can be easier or harder deppending on the game, but if you do get it right the effect is great. You can naturally move your focus around the scene with your eyes and it works just as you'd expect, great sense of depth and all that. Tried it with OoT (running by grass with Epona or staring up to the top Gannon's castle and then down the pit look great) and Mario64 (it's kind of like having a remote controlled toy Mario :P The trees look nice but if you're far away and above and move the camera sideways it's kinda bizzare).
You can also try it on newer-yet-no-so-new games to get a sense of what to expect. It rocks on Fable, having a torch between you and the camera makes for a great effect, but the best part is that 3D makes Fable's main mechanic all that more fun, since you can actually feel just how far the chickens are flying.
Then again, it's nothing game-changing (since those games were not actually made for this), the effective screen gets smaller (using a 22'' 4:3 screen makes it seem maybe a bit larger than a DSi LL screen so not that bad, but for 16:10 it should look a lot smaller) and I don't think you should really use it for extended periods of time. Using it for 30 minutes or so when you stop and try to read something or look at any image on a 2D plane it seems like your eyes keep trying to focus it so it gets 3D lol. But it works well and isn't that demanding n hardware. It's worth a look if you ask me.
