Martin Fowler defines blue-green deployment here: http://martinfowler.com/bliki/BlueGreenDeployment.html
The general idea is that website deployment is done by creating an independent instance of the site, and only redirecting customer traffic to that instance after it has been fully prep'd and verified.
I wonder what open source code is out there that uses a blue-green deployment implementation. I am looking for reference implementations, preferably in .NET.