MIT Robotics expert Jeff Lieberman also is a photographer, artist and inventor who wowed the blogosphere two years ago with his first floating lightbulb, which "uses a special bulb, inside which magnets and circuitry are hidden. Using a magnetic hall effect sensor, an electromagnet, and a [modified] PD feedback system, it floats a lightbulb stably in the air, while power is transmitted wirelessly from the base of the sculpture into the bulb. LEDs in the bulb rectify this AC power and convert it to light."
Now two years later its upgrade time. The new version "operates at much higher wireless transfer efficiency [ie is brighter for less expended energy] and levitates at roughly 2.5" from the nearest object."