We have a fairly common last name, so bill collectors are always trying to get us to pay for someone else's bills. They wouldn't take the hint nicely, so one day, when they asked if Miguel was there, I flew into a rage, telling him that he moved out w/his younger girlfriend months ago, and he owes me money too! Then I'd ask them if they knew where he was, b/c I wanted to find him and get my money back. They never called back after that.
Hubby Mike was sitting in the living room one day when I pulled this routine, and he was very confused. We had a good laugh once I explained what I was telling people on the phone!