I recall two - relatively recently.
The first asked for my mother by name?
(Why? She died in 2009!)
I said she wasn't available right now, but I can give a forwarding address.
I gave the Asian sounding caller, whose name was, er, Kevin, the address of the local cemetery.
The second was a character who did not stop for breath whilst he expounded the virtues of car insurance. He asked me if I knew much about the subject - well, I said, truthfully, that I did not.
He then rattled on for ten minutes, his tongue going at warp factor five, before I asked if he would answer a question?
"of course, sir!" he said.
"Does it matter that I'm blind?"
He swore and rather abruptly ended the conversation.
I was rather chuffed......