This pic shows one of my favorite lighting solutions.

Using a receptacle conveniently located on the wall of the stairwell, someone first plugged in a switch- a device that was once often seen. From this they ran a cord/plug assembly (probably from an old appliance), made a "flying splice" to a piece of romex, ran that through a hole in a stair riser, and on to a surface-mounted keyless in the under-stair closet.

- renosteinke