I don't seem to have a problem anymore with telemarketers. My secret - I turn the calls around back on them.

Ring ring
Hello
Hi may I speak to so and so
Speaking
Hi Im so and so from ..
HEY Im SO glad you called how are you?
Fine I was calling..
Oh Im doing fine do you mind if I ask you a question?
(then before they answer I start asking)
Which do you prefer mcdonalds or carls jr?
Swimming or bathing?
movies drama or porn?
straight on sex or forplay?
and I keep interupting them and asking questions each weirder than the one before is until THEY say they have to go.

And I never receive a call from that same number or company again.