What do you say to those christians who go door-to-door preaching to everyone?

These are my least favorite type of christians. The first thing I usually say is simply "Go away." The other day, that didn't work so I told them that I was an atheist and that they couldn't change that. It was hilarious, the look on their faces. They couldn't have left faster if I said that I was a cannibal. Now I am actually hoping more of them come just for the entertainment value.