LHC@Home is a new "closed beta" BOINC project Their page is located at
http://lhcathome.cern.ch/.
This project is at capacity (reached it in 24 hours after posting for beta testers), and they will not open for the public until Sept 29th.
The Large Hadron Collider (LHC) is the world's largest scientific instrument. It is currently being built at CERN on the outskirts of Geneva, Switzerland. When it is switched on in 2007, it will accelerate beams of protons to unprecedented energies in a 27km long circular tunnel.
You can learn more at
"What is LHC?" or the project page is
LHC@Home
They have stated they hope to expand it other platforms. Currently this project is only Windows compatible, due to the work units, not due to BOINC. It uses the same BOINC clients as other projects.
NOTE: This project is used to help "build" the LHC. It is not clear if it will continue past the construction.