I came accross this pretty neat project called SETI@home...
For those of you who have seen Contact, you may have heard of the SETI Institute. For those of you who have not, put simply, their whole purpose is to explore, understand, and explain the nature and origin of the Universe. (SETI stands for Search for Extra-Terrestrial Intelligence)
They do many computerized tests and use powerful equipment in order to process all the information they receive. (Again, the movie Contact tells a lot about the nature of their work more than I could ever begin to...) But the organization is constantly needing more and more computer processing which is why they have developed SETI@home (which has now evolved into BOinc (I know, it's alphabet soup... but stick with it).
This is basically a screensaver type of program that any individual can install on their computer and allows SETI to borrow your computer resources to process signal analysis on a downloaded 350 kilobyte "work unit" of SERENDIP IV SETI radio survey data, and then reports the results back over the Internet. All while you're not using the computer. (They determine the amount of information that they process on your computer based on the specifications you provide them and you can set how much resources they use.)
I found it to be an excellent program and a good cause so I thought I should share. For more info, check out:
http://www.seti.org/
http://setiathome.berkeley.edu/
http://boinc.berkeley.edu/