I just started looking into TeamCity from JetBrains and wow this CI stuff is pretty cool! "TeamCity is a continuous integration and build management system." I've really been meaning to do more unit testing and now that I'm running TeamCity I feel the need to write tests even more to get the full benefits. They have a lot of neat features, support various build configurations, various triggers and they have a few add-ins that make managing your project very streamlined. Having never messed with any type of CI tools it was a little difficult to understand how to integrate my project but I actually didn't end up needing to read any of the documentation and was able to get going in about an hour from install to finish.

TeamCity has a free version (limited) as well as paid versions. I'm currently using the free version since I'm working on small projects.

If you're curious about CI or want to give yourself a real reason to start up your unit test writing then check out TeamCity.

Update:

Here's some more info and a tutorial to get you started.