[First, three links:
• The current puzzle 
• Our puzzle-solving guidelines 
• A Nation puzzle–solver’s blog  where you can ask for and offer hints, and where every one of our clues is explained in great detail.]
Like those of the ancient Jews, the lives of many American puzzle aficionados revolve around three major holidays of pilgrimage. One is the American Crossword Puzzle Tournament , held in February or March at the Brooklyn Bridge Marriott; the second is the annual convention  of the National Puzzlers’ League, which rotates around the country (and sometimes Canada) each July. The third took place last weekend, when many hundreds of puzzlers of every age and level of expertise gathered in Cambridge, Massachusetts, for the MIT Mystery Hunt .
For a certain kind of puzzle fan—let’s say those for whom difficulty is no object—the Mystery Hunt, which is held annually on the weekend of Martin Luther King Jr.’s birthday, represents the high point of the year, the ne plus ultra of head-cracking revelry. The event, whose history goes back more than thirty years, is a single weekend-long quest to be the first team to locate a hidden gold coin.
But of course the coin is merely a MacGuffin. The point of the Mystery Hunt is the puzzles—cascades of them, dozen upon dozen, each interlocking with the others in intricate and unforeseeable ways to create an elaborate pyramid of solving.
What kinds of puzzles? Well, one of the joys of the Mystery Hunt is that there is no single answer to that question. There are word puzzles, to be sure—crosswords (cryptic and otherwise), anagramming challenges and a host of others—but those only scratch the surface. There are physical challenges and jigsaw puzzles; there are knowledge-based problems and performance puzzles; there are plenty of puzzles based in math, science and technology (the MIT roots run deep).
But there are two characteristics of Mystery Hunt puzzles in particular that define the genre, and that keep solvers coming back year after year. One is that instructions are almost never given explicitly—for any puzzle, figuring out what the heck you’re expected to do is generally the first step. The other, related fact is that most puzzles are multi-stage—and the solver rarely knows how many stages a puzzle entails. You might be called on to solve a series of anagrams, but then you have to determine what to do with those answers. Anagram the initial letters of the first round of answers? Consider them to be a cryptogram? Rotate them ninety degrees? Anything is possible, though there are often subtle hints to point you in the right direction.
The result is a marathon of tag-team puzzling—this year’s Hunt, the longest to date, ran seventy-five hours. Teams of solvers, ranging from handfuls to more than 100, come and go throughout the weekend, handing off uncracked or half-solved puzzles to their teammates. And because there are always more puzzles to be solved, you can take the process as seriously or lightly as you choose. Some solvers actually get some sleep, while others prefer to wait until Tuesday.
Best of all, the Mystery Hunt fosters an inclusive spirit. Because the solving teams are so large and elastic, there is always room for an extra brain and one more pair of eyes. You don’t have to be part of an existing team to participate—in fact, thanks to the magic of the Internet, you don’t actually have to be in Cambridge at all (although it helps). All you have to do is show up, ready to solve puzzles.
Have you participated in past Mystery Hunts? Please share your experiences here, along with any quibbles, questions, kudos or complaints about the current puzzle  or any previous puzzle. To comment (and see other readers’ comments), please click on this post’s title and scroll to the bottom of the resulting screen.