I've left my scarf in a restaurant--of course they still had it when I went back.
Alek left his winter mittens in another restaurant. A week later, when I was finally in the same neighborhood again, they were tied up neatly in a bag and hanging in the back.
Max, as you may recall, left his bag of books in the Amanohashidate train station last February. We picked them up later at the koban where they had been duly registered.
Then there's the time Hugo left his Lego guy in Kura Sushi, and the cashier ran after us for two blocks to give it back.
One time when I got to work, I realized that my yellow mitten had bounced out of my bike basket somewhere. I retraced my steps on the way home, and found it on a bench.
Alek fell off his bike once, and didn't notice that he'd also dumped out all of the bottled drinks he'd been carrying in his basket. When I went back to look for them later, someone had picked them up and put them carefully to the side.
Recently I left my empty bento box in a taxi (I was probably distracted by the taxi driver's extensive knowledge of Major League Baseball, including every last Philly). A few minutes later, he came running into the boys' school with it (a block away from where he dropped me off).
So far the only thing we haven't found has been one of Hugo's early BeyBlades, left on a bench in a kids' park. Probably some foreign kid took it. (Only kidding.)
So, sure enough, Hugo and I found the bag of posterboard sitting right on the ground where he'd left it, 4 hours before.
I could get used to this.