Allow scientists to use your computing power

The software delightfully named BOINC (http://boinc.berkeley.edu/) allows scientists from around the world to use your computing power to run their research projects. That might sound faintly creepy, except that these researchers are working on projects like malaria control and climate change forecasting. You can choose from a list of projects (e.g. 'Factorization of large integers' might be right up your alley) and the software won't affect the running of your own programs. This may be the easiest way to contribute to scientific knowledge ever.


Effort involved: just a download. With 'volunteer computing' you're signing up your computer to volunteer, not actually getting dirty yourself.