I tried to join LHC@Home from the BAM Menu->Sign-up for projects link. It told me the project was down,however,clicking the link for it brings me right to the project homepage.

I decided to make an account with matching credentials and try and use the "Find existing account" option but that just changes to either "Searching for existing account" and hangs or it tells me the project is down. Which it isn't.

They're working on consolidating all of their projects into one, they may have gone through a URL change that didn't get caught by BAM.