This is pretty killer, especially for those of us with inconveniently-placed light switches: Three guys in France (Nicolas Triboulot, Laurent Grapin and Thibault Thomas) have patented a system of paint and an unspecified electronic mechanism that can be used to turn an entire wall into a light switch.
No need to pull any electric wires, the switch can cover a large surface. The switch disappears visually and the electronic mechanism remains hidden. It is accessible almost anywhere, whether in zig zag corridors or in large rooms; the switch is everywhere without being seen. The contact area location and dimension can be chosen easily, whether a strip, a whole wall or an isolated area.
Arms full of groceries? Don't feel like getting out of bed? This sounds like a good solution to either of these things. Unless you have a smart dog who figures out he can kill the lights anytime he wants with his nose.