In the morning post, there were two bulging green envelopes. They looked like greeting card envelopes, only containing something that obviously wasn't greeting cards, and bore Irish postage stamps. They were addressed to a house in a nearby street with the same number as my house; apparently the post office mistakenly dropped them in my mailbox.
In the evening, as I was setting out to buy some groceries, I took the envelopes and went to the street where they were addressed to. As I approached the house, I noticed a middle-aged woman walking back to the door. "Excuse me," I said, "is this number --?" "Yes."
I handed her the envelopes, saying that they ended up in my mailbox. "How did you get these?" she asked. "I live at number -- ----- Street. The postman must have accidentally dropped them in my mailbox."
"Oh, thank God for that. I've been waiting for them all day. They contain fresh shamrock for St. Patrick's Day. Thank you for bringing them to me."