Whenever anyone tries to get to the project page (Home > Projects), they get the error:
Error 500 - Internal Server Error. The server could not retrieve the document due to server-configuration or other technical problems. Contact your site administrator.
I also checked the error logs and see these two errors:
Service call failed for portlet: projmgr.projectList_odf
rollback exception java.lang.StackOverflowError
This appears to have happened randomly. It worked Friday, but today (Monday) it does not. Nothing has changed since then.