One of my best friends moved to Denmark. He then sent me a letter written in Danish, knowing that I wouldn't understand the language. But I had an answer to this. Little did he know there was a girl in one of my classes who had emigrated from Denmark.
I had never spoken to her previously. I took the letter to her and asked her if she could translate something from Danish for me.
She said, "Sure," so I handed her the envelope.
She looked at it and freaked out, "How can this be? What is going on?"
I said, "What do you mean?"
She said, "How did you know? Is this some kind of joke?"
I had no idea what she was talking about.
Finally she said, "The return address on this letter is my old house!"
Turns out my friend had moved to her old address, just a complete coincidence.