There is nothing better than a mystery, and this one is better than any I've ever encountered before, outside of Miss Marple.

In today's mail, a buff-colored envelope, addressed to me. No return address. Inside, a white windowed envelope. And inside that envelope is a letter and a folded slip of paper, with a $10 bill showing through the window.

The text of the letter is bookended by red hearts, and it reads: "Thank you for opening the envelope. The money is real. We are all parts of each others' stories. Let's create more together. Please join the project! Use the hints. Find me."

So what are the hints? There are four:

On the back of the buff-colored envelope, it reads, "A literary art project from ATL/w [heart]."

On the back of the white envelope, "Follow your narrative urge! #56."

At the bottom of the letter: "a site to see (haiku clue) robotic cranes dance/ in singapore. in taiwan / appears tornadoes!"

And the folded slip of paper contains a sentence from somewhere--a short story? A novel? it reads: "56. She asks you how your day was and you have to pause, take a second, because her face has something in it, looking at your face -- like it's a real face wondering how your day really was, and not just an extra-friendly coffee girl chatting up the customers."

(Do you recognize this? Because I don't.)

So of course I stared at all of these pieces of paper for quite some time, trying to figure them out. It didn't help that the postmark was blurry, so I could not tell if this strange missive came from Minnesota, or from somewhere else.

What kind of a clue is the haiku? Is it an anagram? Hidden meaning? An elaborate metaphor? And what about the story snippet?

So when I really should have been doing something else, I spent a happy hour or so poking around in my brain (not very productive) and on the Web (much more productive) and eventually found a wiki page devoted to figuring this out. Some of the earlier clues were posted, though I have to say that they don't all add up to much of anything, as far as I can tell. (I'm a journalist. I am black-and-white. I am literal minded. I am not good at puzzles.)

I joined the wiki, added my clues. Am I really clue No. 56? Has someone really sent out 56 $10 bills to strangers along with mystifying literary snippets?

If so, could there be anything cooler under the sun?

The robotic cranes are on Youtube, dancing gracefully. They are 10 storeys high, as are the tornadoes. So there is a signficance to 10 storeys--are there 10 stories? My mind is starting to hurt. (5 p.m.update: A reader sends a better Youtube link here.)

All of this apparently started in Atlanta (which is the simple explanation for ATL), which was sprinkled with these mysterious envelopes earlier this year. Creative Loafing got one, and blogged about it. So did a few others--galleries, and alternative press, and random people.

Buff-colored envelopes containing $10 bills and clues were found in trees, and in public restrooms, and tucked between pages of a book at A'Capella Bookstore. It is thrilling, absolutely thrilling. A sweet mystery of story and word and clues and generosity. Word spread, quietly.

A little more poking reveals a Facebook page, ("follow your narrative urge," the envelope said, so I did) which hints, on Aug. 12, that the art project (for that is certainly what this is) has mostly been solved (though how? where? and what?) in Atlanta and has now expanded to Chicago, Baltimore, Detroit ... and Minneapolis. That's us, Bloggies! Let's put our minds together to figure this out.

And help me spend the $10. It's just a small amount of money, but it should be spent wisely--donated, I think, to something just as charming, as tiny, as fascinating, as original as this $10 art mystery. Don't you think?

2:45 p.m. update: A brilliant copy editor here just sent me the following message:

I plugged 'not just an extra-friendly coffee girl' into Google. It's from 'After the Kiss,' a 2010 book for teens by Terra Elan McVoy.

One more little piece to the puzzle. But what does it mean?