Parallax Barrier 3D for around $5! - This 8-Bit Life
Over at the Meant to be Seen forums a member named Cybereality has made a pretty impressive (and inexpensive) no glasses 3d setup. He’s using a licensed copy of the iZ3D driver, a common LCD monitor and some basic calculation to create a parallax barrier from printable transparencies.
For those of you who are unfamiliar with the concept, parallax barrier displays work on a very simple principle. You see it any time you look out of a car window while it’s moving. The objects nearest you appear to be moving faster than the objects behind them. This is a function of your point of view moving along a y-axis that is parallel to a vanishing intercept point.
This concept can be used to trick the brain into thinking it is seeing a 3-Dimensional image when it it isn’t. This effect is achieved by laying a film of plastic with equally spaced white and black lines (very thin lines) that, when viewed from either the left or right eye respectively will only show an image from one perspective. When your brain processes the two separate images from your eyes it creates a virtual 3D image. This is where the iZ3D driver comes in as it interleaves the same image from two perspectives in straight, vertical lines.
Here is a video of Cybereality describing how he does it and showing examples. Also the first link up top takes you to the forum post containing the tutorial if you want to try it yourself.