NOTE: This post was originally published as "My Unsolved Riddle". However, The Observer solved it today, in a comment. Which makes him a jolly good fellow, which nobody can deny.
I haven't published his answer as I don't want to ruin it for anyone else who comes a long and fancies a pop.
(To my mind, it also shows that it's not an unfair riddle, since someone did crack it eventually.)
If anyone desplerately wants to know the answer, they can email me and I'll tell them.
I'm not good at riddles. I rarely manage to solve them at all. And when I do solve them, it's usually with great difficulty.
A colleague mentioned this old riddle to me, which you have probably heard before but which I hadn't, and that took me about twenty minutes and a wrong guess to work out: "The one who makes it doesn't want it. The one who buys it doesn't use it. The one who uses it never sees it."
So I'm no riddles champ myself.
But I did come up with a riddle that nobody has ever answered correctly (and people, when they hear the answer, acknowledge that it's a fair riddle).
This is it:
A man walks into a shop. He makes a purchase, in cash, that costs twenty euros (or dollars, if you like), and he doesn't buy anything else. He is the only customer for the duration of his visit to the shop-- nobody else comes in or out.
But there is exactly the same amount of cash in the shop after he leaves as there was before he came in. How?
P.S. The Observer suggests that the customer bought an item and then immediately got a refund. This is a fair answer to my riddle as I worded it, but it's not the answer I had in mind. So I am specifying that he leaves the shop with the purchase. Also, buying something and getting a refund immediately is somewhat unusual-- the actual answer is something not in the least unusual, though I admit that the answer lies in additional element that I haven't mentioned (but which might very reasonably be expected in a shop).