I love it when people mess with telemarketers, which is why I'm pointing you all to the footnote of Russ' latest post on the Daily Yak. He says his son loves talking on the phone, so whenever he gets a sales call he just hands the phone to his boy. "Want to sell me something? You gotta get through the kid first!" Simple and perfect. This is an idea I'll definitely be using in a year or two.
In the meantime if you want some more fun stuff to do with telemarketers, print out the Anti-Telemarketing Counterscript and keep it near the phone. (And I would be remiss if I didn't mention the genius of Jim Florentine's Terrorizing Telemarketers comedy CD series.)