Robocall Krytonite

As much as I would like to take credit for this solution, it has already been invented. Simply use Google Voice services as a means of filtering all calls. I am sure you are already familiar with this service, also formerly known as "GrandCentral". Here is a little history: http://techcrunch.com/2009/03/11/grand-central-to-finally-launch-as-google-voice-its-very-very-good/ .