If just flipping a switch to turn a light on or off is too boring you, sudomod has a guide to convert an old Nintendo Zapper into a controller for turning your lights on and off.
To do this, you'll need two Arduinos, one in the controller and one in a box next to your light. Then, you'll set up an IR receiver so you have something to point the Zapper at. This is probably one of the most absurd ways you could possibly turn a light on and off, but that doesn't make it any less amazing. Head over to SudoMod for the guide to make it for yourself.
Lamp Zapper Guide [sudomod]