Many scientists research projects that will extend the life of humans. These scientists do a lot of computer simulations before they do actual laboratory work. For example, in one project concerning a tropical disease known as Schistosomiasis that kills 200,000 persons every year, the scientists estimated that with the computing resources available to them, it would take 30 years to do all of the simulation work necessary for them to choose actual drugs to be used in the laboratory research. But, by using the unused computer (CPU) cycles of many computers they expect to get the simulations completed in one year or less. In this case, they are using the CPU cycles of many of the hundreds of thousands of computers connected as part of World Community Grid (WCG), a grid of computers sponsored by IBM. WCG currently has 11 active projects and has completed 9 projects since its first operation in 2004.
I have two computers connected to WCG, and these computers use clients provided by software known as BOINC. The BOINC servers send the results of my simulations to the scientists doing the research. I've been a member of WCG for about 3 1/2 years. I like WCG because it has multiple projects, and I'm able to choose the particular projects that I will simulate.
There are many individual projects that run on BOINC that are not part of WCG. Before I went to WCG I participated in several individual projects, including searching for radio transmissions from other worlds, a climate prediction project, a project in folding proteins, and a project concerning the cosmos. I went with WCG because I like the humanitarian basis of its projects (e.g. diseases, natural disasters and hunger).
If you would like to enjoy the satisfaction of using your computer for public service, consider donating unused CPU cycles to WCG or to one or more of the individual projects. To get started, go to https://boinc.berkeley.edu/