Last week we had interesting problem described on the tfs forum: http://social.msdn.microsoft.com/Forums/en-US/tfsversioncontrol/thread/f1486665-02b5-42c1-bc4d-bbc29169670f 

The problem:

How to version control only specific folders inside a website. Please keep in mind, we are ordinary user, not a project creator. We don't want to reimplement GetSccFiles :) We have c:\workspace\nuke website full of folders, but we want to version control only App_code and DesktopModules folders.

Solution:

workspace mappings. The website will be still reporting some errors, but cloaking root of the website and mapping only specific folder allows us to get exactly what we wanted:

$/tp/nuke/DesktopModules - c:\workspace\nuke\DesktopModules

Enjoy!