Grow your own testing framework
Ben Hall has written an interesting post on creating a testing framework with MEF. As Ben said it is more a learning exercise for MEF than a useful product but it certainly show show the ease you can add meta data and reflection like functionality to your codebase. Wish it had been about when I wrote GUITester
Read the complete post at http://blogs.blackmarble.co.uk/blogs/rfennell/archive/2009/07/09/grow-your-own-testing-framework.aspx