Apple has patented a 3D projection technology. Using an "angular-responsive" surface, light sensor, projector, and "3D imager," the system creates a three dimensional hologram. As the observer's position moves, the system adjusts in order to sustain the illusion.
Imagine, all that stuff was in R2-D2. Simply amazing.
Links:
[1] http://www.maclife.com/article/down_with_copy_protection_linkin_park_in_the_big_apple_multi_touch_patents_and_more
[2] http://www.maclife.com/article/iphone_firmware_2_0_images