Instructions: As you look at this picture cross your eyes until the two images overlap into a third image between the first two (I find it easiest if you focus on lining up the bamboo in the middle of the table). Once you get it lined up the picture will become magically three dimensional.
There was an issue of a photography magazine (I don't remember right off which one) that was dedicated to 3D pictures and even included a set of those funky two colour glasses. After I read it I tried my hand at a few. They're much easier to do with proper equipment and technique but this one seems to work reasonably well.
If you're a flickr-fan you can check out the stereophotography group for more 3D fun.