We recently revised the organizational structure of some source code, and as a result projects now resided in new locations on disk. I've a big fan of the MRU list, and make use of it often in visual studio (both via the File->Recent Project/Solution menu option and the quick links available on the VS start page). The reorganization of my code base orphaned this links. I was unable to locate a UI for managing this list within visual studio, but did locate the source of these lists in my window's registry.
HKEY_CURRENT_USER\Software\Microsoft\VisualStudio\9.0\ProjectMRUList
Open RegEdit (or your favorite registry editor), migrate to the above locate and modify/delete the MRU list presented within.
It's the small things that speed along the work day, don't you think?