http://www.worldcommunitygrid.org/

World Community Grid enables anyone with a computer, smartphone or tablet to donate their unused computing power to advance cutting-edge scientific research on topics related to health, poverty and sustainability. Through the contributions of over 650,000 individuals and 460 organizations, World Community Grid has supported 23 research projects to date, including searches for more effective treatments for cancer, HIV/AIDS and neglected tropical diseases. Other projects are looking for low-cost water filtration systems and new materials for capturing solar energy efficiently.