There are some funny recordings of what people do when answering telemarketers on Youtube. The funniest one was as soon as this one man would answer the phone he would say "911 what is your emergency?" The caller would say I'm sorry I didn't call 911. The man would go into this long tirade about how it's illegal to call 911 if you didn't have a legitimate emergency and starts asking for the callers name and phone number. The next thing you'd hear is a click.
At my house 800 numbers go un-answered and if a call shows up as "Unknown Caller" on the caller ID, without picking up I say "Unknown Answerer" and go about my business. It's always a waste of time to try and request that they take your name off their list.