This is a demo of software that uses a Wii remote to track where your head is relative to the screen. The software can take that information and change the image on the screen to give the illusion of a "window" into a three dimensional space.

This is very different from the technology used in, e.g., a 3D IMAX movie. In those movies, you wear special glasses that cause slightly different images to be seen by your right and left eyes. The small differences between the images is interpreted by your brain as depth.

With the technology shown in this video, the illusion of three dimensions is produced by parallax when you move your head around. Parallax is what happens when things at different distances move across your field of view at different rates. If you look out the window of a moving car, trees that are close to you move much faster across your field of vision than trees that are far away from you.

Head tracking is even better than conventional 3D for games, because (as demonstrated at the end of the video) you can move around your living room and change your line of sight. The effect is truly immersive.