BOINC is a program that lets you donate your idle computer time to science projects like SETI@home, Climateprediction.net, Rosetta@home, World Community Grid, and many others.
Once BOINC is installed on your computer you can connect it with as many of these projects you wish. You can use the idle time on your computer for many purposes, including to study global warming, cure diseases, discover pulsars, or do other types of scientific research. It's easy, safe, and secure.
BOINC supports 64 bit Intel project applications on OS X 10.5.0 or higher. However, the screensaver coordinator for OS X 10.6.x or later is the only BOINC client package that has been built as a 64 bit executable. BOINC libraries are also available in a 64-bit version so they can be linked to 64-bit project apps.