AppVeyor is a hosted continuous integration service for .NET platform.
It can be a good alternative if you don't want any to host a CI system like TeamCity on your own server.
It is a commercial service, but free for open source projects. I have never tried it but I just put it in my blog just in case I need it someday.
Scott Hanselman has a good article about it.

UPDATE: I have used AppVeyor for my OSS, NDummy and it is configurable easily.