The SETI project from Berkeley has been around for years. With unused PC cycles, the SETI software performed the math necessary to determine if telescope reading at Berkeley might contain data from extra terrestial signals. While that software (with the familiar black screen saver with the 3D bar chart) is no more, about a year the SETI project became part of an even bigger project. The BOINC project uses the same PC cycles from volunteers on a number of other projects, such as identifying new prime numbers, a genome project, etc. Read more about the whole phenomenom in this article.