Telemarketers - How do you deal with them?

hehe... this one is quite good:

<me> hello
<them> hi, i'm calling from ABC and would like to know if you're interested in our new off--
<me> could you please just hold on a second, i have something boiling on the stove and i just need to turn the heat down. Won't be a second.

I then go off and return to doing whatever the hell I was doing before they interrupted me with their crap, smug in the knowledge that they're wasting their own money waiting for me to return instead of wasting my valuable time. For extra amusement you could just cover up the mouthpiece and stay on the phone waiting to see how long it takes before they hang up, but I imagine it would take a lot of self control to not laugh out loud and ruin the whole charade. In fact, them uttering some profanity against you just before they hang up would make the whole thing worthwhile!

Jam it back in, in the dark.