1. Answer the door naked and carrying weaponry. (immediate results)
2. Pretend to be the slowest talking person in the world and see how long their spirit of Christian charity lasts.
3. 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 get flustered and leave.
your additional sugestions please
Nic'