Google open sources Liquid Galaxy code

At Virginia Tech, we did something similar with back projection called the CAVE. It was a cube (4 sides at least) of back projections large enough that you could walk into it. One of the sides was the floor, which was particularly challenging to set up. All of the projections were also 3D using glasses that used quick on/off flipping (better IMHO than the polarized things at movie theaters) and the system had physical devices (we called them wands) that new their 3d location inside the cube. Essentially, we had what seemed like a first generation "holodeck" (trademarked term unfortunately). Someone somewhere had even modified quake to work in this environment with the wands controlling the location of your gun in 3d space. It was pretty interesting.

Of course, I'm not sure how practical something like this is, and it's very expensive to build.