Telemarketers read off a script. I found a script for anti-telemarketers to use.
If you have some spare time, you can waste their time!

The website also has lots of information to get off junkmail lists.

http://www.junkbusters.com/ht/en/script.html

Stolen response set #1:

* "Hi, I represent the Acme Widget Company. We're offering..."
* "Wait a second. Are you naked?"
* "Excuse me?"
* "Are you naked?"
* "No, I'm not. We..."
* "I'll only listen to your sales pitch if you're naked."
* "Sir, I don't think that..."
* "Do you want me to listen or not?"

Stolen response set #2:

* "Hi, I represent the Acme Widget Company. We're offering..."
* "Hey, I'll listen to your sales pitch, but could you do me a favor first?"
* "What's that?"
* "Could you talk to my plants for a minute?"
* "Excuse me?"
* "They're upset with me right now. Maybe you can talk some sense into them."
* "...Your PLANTS?"
* "Yeah. Tell them that they have well-shaped leaves and smell nice or something. Okay? Here's my row of begonias."
* "..."

*coughs* speaking as an ex telemarketer ( or is that telemarketeer?) I gotta just say.....give these people a break. For you its a few minutes of annoyance for them its a day ( or evening) long drag of dialling peoples numbers watching the scoreboards, feel;ing the pressure getting sexually harrassed by the fieldreps( ok maybe they dont all but thats my experience) and threatened with dismissal if they cant meet their quotas......
is it too much trouble to just say

"Yeah, look I know you are just doing your job, but I dont have time for this right now/dont wish to hear about your services. Thanks for the call though."

Usually the people working those jobs are doing it because they havent any other options available to them which they can reasonably pursue. They are usually the members of an organisation who are treated the worst and have the fewest legal protections. They are also usually calling off canvass sheets which they have to trawl through again and again. Many of the jobs I had ( and they never last long) the managers were reluctant to "waste" new leads on you until you had thoroughly exhausted the canvass sheets you were working through. Consequently i made many calls which I knew to be stupid, knew would result in nothing but aggro but had to call because to do otherwise would have led to my sitting inactive with no calls to make and a supervisor explaining to me why I was no longer needed.

You could have turned to a more honorable profession, like prostitution, or murder for hire.

Arm or leg?

What dialing? They've got automated predictive dialers which connect them to me after I pick up. Or, if they don't have enough drones, I get silence.

Yes, it is. Particularly when I would have to say that many times a day and NOT get paid for it.

Have you considered panhandling? Cuts the middleman right out.

Why should I be polite to someone whose job it is to annoy me, just because it is their job?

Every telemarketer fired is one more round of minimal training for the new hire, decreasing the profit to the company. Likewise for wasting the time of a telemarketer.

wow, a profession more disliked than mine
nice!