Had a telemarketer who kept calling me in spite of the fact that I asked to be removed from their list (something they are required to comply with, by law). They called for 5 days in a row, always during dinner.
In a very polite tone, I asked the telemarketer for his own home phone number.
Puzzled, he asked me why I would want that.
The response of course, was so that I could call him up during his family's dinner hour to hear his spiel.

Somehow, a dim little light bulb finally clicked on in his head. He actually apologized(!) and then made sure to have our phone number removed from his list. We've never heard from this company again.