Motion Sensor Lights.

Motion can be detected by measuring change in speed or vector of an object or objects in the field of view. This can be achieved either by mechanical devices that physically interact with the field or by electronic devices that quantify and measure changes in the given environment. Motion sensors are often used in indoor spaces to control electric lighting. If no motion is detected, it is assumed that the space is empty, and thus does not need to be lit.

I liked the underground car parks motion sensored lights to guide you through the dark empty space. It gives the space and eerie feel as if someone is watching you. Below are some videos of other types of kinetic lighting installation which I find interesting.

http://news.cnet.com/8301-17938_105-20007630-1.html

http://www.beaconinstallation.com/#bottom

http://www.youtube.com/watch?v=BHGaW8lBlSk&ob=av2e