A fact of which most people are unaware is that many telemarketers are employed under the Americans with Disabilities Act. They are crippled, have missing limbs, have mental disabilities, phobias, and other such problems. A lot of people get into telemarketing because they just can't do anything else. So be a little compassionate, because you don't know what situation the person on the other end of the line is in. Here is the technique I use to get telemarketers to quit calling me:

1. Write down the name and phone number of the company, the first name of the telemarketer, and the date and time they called.
2. Tell the telemarketer that you work for a competing company (e.g., AT&T vs. MCI). This will get them to shut up and stop trying to get you to buy something.
3. Ask them politely not to call you again. By law, they cannot call you for another year. If they do so, you can sue them.
4. If they persist in bothering you, you now have the right to be a bitch.

This technique has worked for me. And remember, the telemarketer has your name, address, and phone number. Do you really want piss off someone you don't know who has this sort of information? Besides, we could all do with a little less hostility.