Thought of two:
1. I had just checked into a hotel at the beach, back in college, when the room phone rang. I answered it:
Pleasant-sounding male voice: "Pinky?"
Him: "Hi! It's Paul!"
Me, running mentally through the short list of male friends I have with that name: "Um...hi!"
Him: "How are you?"
Me: "Fine...I'm sorry, who is this again?"
Him: "Paul, that you met on the beach this afternoon?"
Me: "Um, I'm sorry. My name IS Pinky, but I think you have the wrong person. I just got here, I havent met anyone at the beach."
Him sounding hesitant and embarrassed:"Um...OK. Very sorry to bother you."
He sounded like a nice guy. I was sort of envious of the other Pinky.
2. For awhile, once a week or so I would get a phone call from the same number, and when I answered it would just beep at me. After quite a bit of detective work, it turned out that it was a dedicated outgoing fax from a grocery store. Evidently our number got put in as one of their distributors', and their order fax would try to come to me.
Since it was a fax line and I couldn't talk to anyone, I ended up writing a letter that said, "You are trying to send a fax to a wrong number. This a residential number. Please stop the fax and check the number." I would fax it to them when the calls started. After a couple of times, it stopped happening.
ETA a missing word