Have you ever heard of the BOINC? It is an open-source software platform for computing using volunteered resources. In short, you install this utility on your desktop, and it runs in the background (as a screen saver) processing data for a variety of science based projects.
The two projects that I personally favor are Einstein@home which is the search for pulsars or the Milkyway@home which is creating a three dimensional map of our galaxy. And there is also the SETI@home project. (Who has NOT heard of the SETI project?) But there are over two dozen various projects to choose from.
If your PC is turned on and running torrents, then less than 5% of your CPU is being used. Why not share the extra unused CPU processing ability to support one of these projects?