The CastAR is truly unique in both its implementation and its construction.
One of the booths I was most excited about seeing at this year's Maker Faire is CastAR, an augmented reality device by Technical Illusions.
The CastAR is a completely new method of doing augmented reality. It consists of a pair of glasses you put on and a screen you look at. There are tiny projectors in the glasses that project the image on the screen in front of you. Having two projectors allows them to project a set of polarized images that appear 3D through the polarized glasses just like a 3DTV. Unlike a 3DTV, though, this one also tracks your head movements. This means that as you duck and lean, your perspective in the visualization changes correspondingly.
Not only does it have the fantastic feature of head tracking, the use of a retro-reflective screen means that you only see the information being projected by your set of projectors. Multiple people can play on the same screen while seeing completely different images. The possibilities this brings to the table are quite exciting.
I really can't wait to see how this tech evolves. The already impressive display is, as you can see in the video, only a rough prototype!