me - hello?
TM - are you the head of the household?
me - nope.
TM - can i speak to him?
me - he's not here.
TM - do you know when he'll be back?
me - i have no idea. i dont live here.
long pause
me - wanna come over and take a bath with me?
click

LoveandGuns
I usually just hang up after telling them I'm not interested and hopefully they find someone else who might be. Usually they're not pushy on any of their products or marketing techniques, and are pretty polite.

I try to do this as well. Just a simple ‘thanks but no thanks’ and I never hear from them again.

I feel bad for the people who feel they need to make crank calls. Probably some inner self-loathing that's being directed outward towards a person who makes good money. Oh well, we all have our jealous moments

Heehee
Well, I have handled this differently over time. When my nieces were toddlers, I'd give the phone to them. I'd sit close and listen to see just how long the telemarketer would stay on. Some would ask for my niece to get an adult and of course my niece would respond in baby~ish babble. Some immediately hung up, some would continue to ask for a few minutes.
Sometimes I would just put the phone down after answering. Not hang up, just lay it on the couch or whatever and see how long they stay on the line saying “Helllllo?”. One person stayed on a good 10 minutes. Other times I would say “I'm not allowed to make decisions” and quickly hang up.
Now that I have had jobs where I deal with people on the phone (though never to sale, thank goodness!), I have a bit more sympathy and simply say “no thank you, bye”.

bongotezz
me - hello?
TM - are you the head of the household?
me - nope.
TM - can i speak to him?
me - he's not here.
TM - do you know when he'll be back?
me - i have no idea. i dont live here.
long pause
me - wanna come over and take a bath with me?
click

Brilliant!

I always wonder about that “man of the house” stuff…

bongotezz
me - hello?
TM - are you the head of the household?
me - nope.
TM - can i speak to him?
me - he's not here.
TM - do you know when he'll be back?
me - i have no idea. i dont live here.
long pause
me - wanna come over and take a bath with me?
click

I… I… I love you

One of my favorite approaches is:
Me: Hello?
TM: Can I speak to Mr. or Mrs. blablabla please?
Me: Yeah, sure, hold on a second.

And then I just put down the phone and leave it there 'till they hang up.

D0m
Telemarketers. You either hate them, or you -really- hate them. I'm fitting in the latter category right now. I was asleep on my couch, and got two phone calls within a five-minute time frame. I decided to answer the second time, and got this.

Me: Hello?

TM: Hello, sir. Are you the man of the house?

Me: I guess. Look, I'm not interested.

TM: No, No, I'm with Direct Marketing _______blah blah, and we're starting a new promotion.

Me: I'm not interested, sorry.

TM: No, don't hang up. Don't you want an all expenses-paid trip?

Me: No. I live in my basement.

Then he hung up. What a bum.

Anyway, does anyone have some funny techniques to throw these guys off?

Usually I hang up… But when no one else can hear I usually tell them: “I don't give a fuck about your damn product!”

I'm not good at putting the phone down on people while they're still speaking (damn my congenital British politeness!), so I usually let them finish their opening pitch but - as soon as they pause for breath - I'm pretty quick with the “No thanks” and promptly hanging up.

The exception is if the same company calls several times. Then I'm more than happy to cut them off in mid-flow!