You can make your own ferrofluid (a liquid that becomes strongly magnetized in the presence of a magnetic field) for experiments
Scientific Tuesdays - How to make Magnetic Fluid (ferro fluid) --this would be fun to put in a sealed discovery bottle and let children watch what happens when they apply a magnet
Ferrofluid climbs up objects that have exposed details and ridges.
Learn how to make your own ferrofluid
How to Make Ferrofluid: The Liquid of the Future « Fear Of Lightning