One many uses for a magnet from a junk computer hard drive

[FixJeeps.com]

Hard drive magnets are a very versatile little tool. If you know someone that works on computers, ask them to save you the bad hard drives. Then tear them apart for the magnets.

For instance this neat little light here was made from a single magnet and a cheap little LED light. Friends have seen them in action. They are very handy because the magnet is strong enough that it will stick solid to metal through the undercoating.