Chris Rieger is the inventor of a light bulb that, thanks to the magic of electromagnetism, He is able to levitate in the air and run to perfection.
Explained in a simple way I will tell you that the bulb has a magnet that attracts it toward the ceiling, as where there is an electromagnet that repels it enough so that it is suspended in the air. In the event that we cortasemos you the power source, the electromagnet that repels it would cease to work and the bulb would be attached to the ceiling thanks to your magnet.
The prototype that we can see in the video below is a LED bulb It uses the same principle electromagnetic that keeps her suspended in the air to feed and thus produce a light source.
I know nothing about the production costs of these bulbs and how feasible that would be filling the part of on top of the roof with the suspension-alimentacion system required to operate this lighting system, but we must recognize that it would be most practical to change the lighting and the points of light in a room simply with move light bulbs in the air.