I love messing around with telemarketers. I mean those who get past the initial "I'm not buying anything" they get before they complete their first sentence. It seems, for some reason, to throw them completely off track.
That, and the "I doubt that, I didn't participate" when you get informed you won a prize, or "Yes I know your brand, no I don't buy and I won't because I don't need your stuff". Some try to be "smarter" and start telling you they don't sell anything, just to run into a wall when you ask them why they called.
Others examples include "We would like to ask you some questions" >> "I don't feel like answering", or "You're wasting my time and unless you get to a quick stop I'm gonna waste a lot of yours".
Not as fun as messing around with the proselytes from the Watchtower Society a.k.a Jehovah's Witnesses ... though, I haven't seem them in a very long time, possibly got blacklisted. Still, I kinda miss their "We would like to talk about Jesus".