When the 'sales person' rings through and suggests that the company they are working for would like to loan you money, tell them you just filed for bankruptcy and you could sure use some money.
When Mr. Asshat rings, especially during your dinner time, when they say they're John Doe from XYZ Company, ask them to spell their name. If the company name is only letters, such as XYZ company, ask them to pronounce the company name, pursue this endlessly then accuse them of not really working for the company as they can't even pronounce it. If their company is a real word, ask them to spell it and get it wrong. Then ask where the company is located, how long it has been in business, how many people work there, how they got into this line of work if they are married, how many kids they have, etc. Continue asking them personal questions or questions about their company for as long as necessary. As long as necessary is deemed complete when they hang up.
When Miss Assmonkey calls and you are a guy, wait for the person to introduce themselves and then in a real husky voice ask 'What are you wearing? I'm dressed in only my underwear, would you like to talk about them?'
If Mrs. Assburglar calls, cry out in surprise, 'Judy? Is that you? Oh my God! Judy, how have you
been?' 9 times out of ten, this will give 'Judy' a few brief moments of sheer panic as she tries to work out where she knows you from.
This is rather childish, but can be effective. Say 'No' over and over. Be sure to vary the sound of each one, and keep a rhythmic tempo, even as they are trying to speak. This is most fun if you can do it until they hang up.
When that goat-felching carpet cleaning company calls, respond: "Can you get out blood? Can you get
out goat blood? How about human blood?"
After the 'sales person' finishes their spiel (the longer the better), tell Mr. Assmunch that you work for the same company, and they can't sell to employees.
Pretend to be hard of hearing and ask them to repeat everything they say, several times. Put on the old fogey voice 'Eh? Dear? What's that you say? Again? Nope, still missed it? Did you say you sell pets? Ey? What?'
After Mrs. Telescum finishes their spiel, advise them you are on 'home incarceration' and ask if they
could send you some beer.