I'm thrilled to present the project I joined last October: 'Pex' (for Program EXploration). Pex is a powerfull plugin for unit test frameworks that let the user write parameterized unit tests**. Pex does the hard work of computing the relevant values for those parameters, and serializing them as classic unit tests.
Here's a short screencast where we test and implement a string chunker. In the screencast, we use a parameterized unit test to express that for *any* string input and *any* chunk length, the concatenation of the chunks should be equal to the original sting.
http://research.microsoft.com/pex/screencast.aspx
More info on Pex is available at http://research.microsoft.com/pex/.
** It's actually much more than that... but let's keep that for later :)