XtremLab
XtremLab is a project running on the Boinc Desktop Grid platform.
Contrary to other projects, Xtremlab does not use the grid for computations about physics, mathematics or biology, but studies the grid technology itself. The project studies actual performances and try to combine various grid technologies in order to find how to improve performances of all others projects.
Unfortunately, the server is temporarily closed. According to the project home page, it will reopened before Friday 07/11/2007. However, more than a month has passed since that date and nothing seems to have happened yet.
Wait and see - there are plenty of other projects to participate in!