post others if you have any ideas:
When they try to sell you long distance, explain that you do not have a phone.
Pretend to be a voice recording.
"Hold on while I get my credit card" - come back an hour later
Ask if they know how to get blood stains out of beige carpet
Try to sell them something.
Ask for their home number and tell them that you'll call them back at a more convenient time.
Pretend like you're on scene of a murder investigation, and say you have to interview them.
Act like an old lady who is hard of hearing and keep telling them to speak up.