This one is relatively simple and low impact, but irritating as hell to whomever you inflict it upon.
All that is required here is a phone call to your local religious cult. Scientologists, Jehovah’s Witness, Mormons, take your pick. Call and say you’d like to meet with them at your home and hear all about their lunacy.
Whomever you send them to will never ever ever ever shake them. They will be showing up at their door until the end of time.