And because of that adding MVC-related file types with Add - New item (eg. Razor view templates) are not available. The currently added project types are "Windows (C#)" and "Web Application".
Here's a corresponding topic on SO:
http://stackoverflow.com/questions/10840263/razor-view-page-cannot-be-added-as-a-new-item-visual-studio-2010
Fix from the last comment: add {E3E379DF-F4C6-4180-9B81-6769533ABE47} to the <ProjectTypeGuids> section. After that, "MVC 4" appears under the "Web" section.
Looking at the file history of "ModuleCsProj.txt" I see that it's been modified a few times with adding/removing the project type GUID of current the MVC-version. It'll break if you don't have MVC 4 installed.