Neodymium iron boron (NIB) magnets are usually called neodymium or rare-earth magnets. They are extremely strong, having a magnetic pull-force that is 10 times greater than ferrite magnets and 20,000 times greater than the Earth's magnetic field. These magnets are brittle as well as powerful and they can shatter easily. If proper care is taken when handling them, they can be put to many instructive and creative uses.
Invisible Tool Holder
Put a 1/2-inch diameter cylindrical neodymium magnet in your pocket and it will act as a tool holder. Any tool with a metal handle or shaft will be held on your trousers by the magnet. If you don't want to risk ripping your trousers, make a magnetic tool belt by gluing button-size magnets to the inside of a leather belt. You can also make a magnetic tool holder for your workshop by drilling magnet-size holes in the back of a piece of wood, inserting magnets in the holes, and hanging the wood on a wall so that the magnets are hidden. Even though you can't see them, they will still strongly attract metal.
If you have a collection of neodymium magnets, get creative and build fantasy structures that seem to defy gravity. For example, build a vertical wooden frame, embed a magnet in the top horizontal bar and glue a second one to a string attached to the bottom bar. The magnet on the string will be attracted to the top magnet and will appear to hang in the air. Use magnets of different sizes and shapes to access your inner artist.
Test Lenz's Law
Slide a neodymium magnet along a nonmagnetic conductive surface, such as copper, and you'll notice that the magnet resists movement, even though it is not attracted to the metal. This happens because the moving magnetic field creates an electrical field in the conductive material, and this electrical field acts to oppose the magnetic filed. This effect is known as Lenz's Law.
Stick two grapes on the end of a straw and balance the straw on a pin stuck through a plastic jar top. Move a neodymium magnet near one of the grapes, and it will move away from the magnet. Then, turn the magnet over. Although you expect grape to be attracted, it is repelled again. This happens because the water in the grape is dimagnetic and is repelled by both poles of a magnet.
Make a Magnetic Generator
Set an old CD on a spindle so that it rotates freely, then glue a small neodymium magnet to the top so that one pole is at the edge and facing outward. Move another neodymium magnet close enough so that the magnets repel each other, and the CD will turn. If you can figure out a way to synchronize the movement of the free magnet so that the CD keeps spinning, you could revolutionize the energy industry.