Before there was a "do not call" list, my parents hit on an idea that I always used. Whatever it is they are selling, take that item away. For instance, if they are selling a subscription to a newspaper, tell them you are illiterate. If they are selling gutters for your home, tell them you live in a cardboard box. If they are selling shoes, tell them you have no feet. There is nothing they can do.
I currently don't have the capacity to watch the demo, but back in the day I'd have long conversations with the telemarketers. Good times... Almost makes me regret signing up for the no-call list.