The Casimir effect is not something that you typically learn about in school, at least as chemists. A vacuum is filled with zero-point fluctuations with a wide range of associated wavelengths, but if two solid objects are brought close together (nanometer scale), some of the wavelengths are eliminated. As a result, the energy in the gap is reduced and there is an observable force that attempts to close the gap even further. Consider it a van der Waals force for large objects, if you will.
The subject is an area of active research, especially with micro- and nano-machines. One popular question asks is it possible to use these fluctuations as an energy source (i.e., free and totally clean energy?)
A new paper (open access though 8/31//2010) in the Journal of Chemical Physics outlines a number of possible cases where the effect could be used to alter chemical reactions. The paper is quite readable for someone with a junior level of chemistry, so please give it a whirl – and then start experimenting. This looks like a neat area to explore.