My boss tells all telephone-company telemarketers that he's not interested, that we have no phones! When the few persitent ones say "how are you talking to me, then?" he says - "tin cans and string, you should try it." Whereupon they invariably give up, and hang up on him!

We have the "No Call List" and are gladly on it. We rarely get calls any more. I was never angry or rude with them, simply said "No thank you" before hanging up.