A group admin somehow managed to rename one of the portlets for her class (specificially, she renamed Assignements to Syllabi). How she did this is a mystery; she could not reproduce the steps when asked. But she did it! She then found that she could not add the renamed portlet to a page; it caused an error (unknown) that broke the entire page.
When the portlet was renamed, its associated file storage folder was renamed also. The site admin renamed this folder back to Assignments manually, then found that she could not create a new folder called Syllabi because the name was already in use. So clearly something did not get renamed behind the scenes.
Finally, the group admin decided to try to recover by reverting the portal page to its default configuration. She ended up with a page called "portal revert dummy page 0".
Sound familiar to anyone?