Ever since Princess Leia uttered her famous words, years of research and development have gone into constructing a true holographic display. The research papers are filtering out of SIGGRAPH 2007, and a team from USC, Fakespace Labs and Sony have a unique take on 3D displays that doesn't require you to wear those dorky red/blue glasses.
Unlike the other holographic displays being developed, the 360° Light Field Display uses a mirror that spins at 15 to 20 times per second and reflects a light beam being projected at close to 5,800 frames per second. If that doesn't impress you, consider the vertical and horizontal parallax is so smooth and perfect you'll be able to walk around the setup and swear you could reach out and touch it. I wouldn't, though, as that mirror could do some pretty nasty damage to your digits.
And lest you think this display will only do stationary objects, take the jump and watch the video that includes a little holographic man taking a walk. He's no Princess Leia, but give the technology to the adult film industry and I'm sure they'll come up with something in no time flat.
You can also find a high-quality QuickTime version here.