No-touch light switches

Yesterday, I walked into a restaurant bathroom. The lights came on.

Motion sensors. It startled me, but was neat.

I was a summer intern Argonne National Laboratory; they had all their lights on motion sensors, and it worked really well. Except that if you were doing something sitting still (such as reading), you had to wave your hand in the air every ten minutes or so (to turn the lights back on). Fun times.