We have our source code stored in Kiln/Mercurial repositories; we use MSBuild to build our product and we have Unit Tests that utilize MSTest (Visual Studio Unit Tests).
There's always BuildBot which I like (and have contributed some code to ). It's fairly easy to set-up and run on any OS, and to do simple tasks like that you say, and remarkably flexible if you need it.
What you might find missing is batteries-included log-scrapers and/or report generators that other more commercial CI-servers comes with, especially for Enterprise-y frameworks.
It scales pretty well too, Mozilla and Chromium use it, amongst others.