A chalk outline of a human body on the pavement, and a few copies of "The Watchtower" scattered around...
Answer every one of their questions with "What do you mean by that?" This might take a while, but you and your loved ones can have fun placing bets on how long it takes for them to leave.
When they ask, "Can I talk to you about God?" Reply, "Sure, what would you like to know?"
Answer the door with a bloody knife and say, "I'm sorry, could you come back in a half hour? We're not done with the virgin yet."
Answer the door with an automatic weapon and say 'Allah be Praised!
Ask them for their address. When they ask why you want it, claim that you want to appear on their doorstop univited so that you can peddle your own beliefs.
Look smug and tell them that your God can beat up their God.