I used an aluminum clip to create a switch. I wired a piece of chipboard with one LED. When the board is clipped into the metal clip the circuit is completed and the LED lights up.
The entire metal clip is conductive so I had to find a way to break the circuit. I attached a piece of felt to one of the inner faces of the clip. I then ran a coated wire along that side of the clip. By doing this I was able to run both the power and ground through the clip. The circuit is only completed when each face of the clip meets the end wires from the LED.
Here is the result: