Hi,
In this instructable I am going to show you how to create and LED desk drawer light that turns on once you open the drawer and turns back off once you close it. It is very simple, cheap and easy to make and is a great light for digging through your drawers with. You can even adapt it to be used for your glove box in your car or any number of things.

Step 1: Materials and Tools

Materials
LED- I used a 10mm diffused white LED. 15-50 Cents. You can take an LED pretty much any old electronic device or buy them online. Radio shack sells them for an arm and a leg.
Coin Cell Battery- I used the CR2032. Very Common. You can get them at radio shack or online. Even Big Grocery Stores have them. They cost any where from 20 cents a piece online to close to $5 dollars at radioshack.
Magnetic Switch- I used one that I took off of an old sliding door. It was used for a security system. You can use either a switch that is always on except for in the presence of a magnetic field or one that is always off except for in the presence of a magnetic field. I used one that was always off. You can buy these online, at radioshack or at your local hardware store. ( Please Shop local, no big box stores. Big Box stores are evil!!!) They cost about $3.
Electrical tape- About 20cm. You could even use duct tape.
Wire- ~15 CM of wire. Any will do. Take it out of an old car.
A desk drawer, glove box etc.
Magnet- I would recommend a rare earth magnet. They are really strong, and pretty cheap. You can get them online or cannibalize them out of old toys, hard drive or any number of electronics. They only cost pennies for small ones. There are some really big ones that cost a lot though. ($100s of dollars!!)
Tools
Wire Cutters- I used my MAKE: Warranty Voider - Leatherman "Squirt" E4 (electronics version) Pocket multitool. (BTW this is the best Mulitool I have ever owned!!!)
Screw Driver- For wrapping wire around the terminal screws.

Step 2: Snip Wires

The First thing you have to do is cut the wires to length. You need 2 ~5cm long pieces of wire. Then strip both sides of the wire. On two of the wires use the screw driver the turn them into a circle and wrap them around the terminals of the switch. Then Screw the terminals in making sure all connects are tight.

Step 3: Add Battery and LED

Now you need to add the battery and LED. First tape the longer leg of the LED (positive) to the positive head of the battery. Then tape one wire of the switch to the negative side of the battery. Now take the other leg of the LED and wrap it around the other wire on the switch and tape them. Now try it out. When a magnet goes next to the switch the LED should light up. If it does not make sure all connections are tight and that you have the LED in the right way.

Step 4: Mounting the Light and Magnet

No we are going to mount the light in the drawer. Basically the light is going to be mounted on the roof of the drawer (were it does not move). Then we are mount the magnet on the side of the drawer so they meet up and activate the light. I mounted the whole thing with electrical tape.

Step 5: You're Done!

Now your done! When the door is closed light is off. When Door is open the light turns on. Great for illuminating the treasures in the doors. If you have any questions, suggestions or other ideas please feel free to comment of PM (personal message) me. Thanks for reading!