OK. Think. "Boss"? No, too obvious. Board meetings. Diving board? Swim meet? No, "meet" is in the clue. Come on …

"Nail," says a voice from somewhere behind me.

I have just blown my chance to impress Will Shortz and Merl Reagle with my crossword-solving skills, but at least I'm not the first person to be shown up by this particular interloper. The mystery voice belongs to Jon Delfin, seven-time winner of the American Crossword Puzzle Tournament, who, like Shortz and Reagle, is in town to promote the documentary Wordplay. A few seconds earlier, Delfin was checking his e-mail (and, apparently, eavesdropping on our interview). But give a puzzler a chance to test his skill and he'll find it hard to resist.

BOXED IN: Will Shortz ponders 34-across.

For dedicated solvers, crossword puzzles are something between a pastime and an obsession, as essential to their daily routine as a morning cup of coffee. As anyone who's ever erased a hole in the New York Times knows, Shortz is the most famous crossword editor in history, and Reagle, whose pun-filled puzzles grace numerous Sunday papers, is no slouch himself. Since the existence of crossword constructors rarely crosses most people's minds, there's probably no stereotypical image for them to defy. But both are personable, gregarious and look like they see ample amounts of daylight.

By most accounts, there are as few as two dozen full-time constructors in the U.S., but Shortz and Reagle have managed to make a living, and a good one at that, by redefining the American crossword puzzle. In the pre-Shortz era, the Times crossword was edited by the notoriously prickly Eugene Maleska, whose grids were filled with head-scratchers like "esne" (a medieval slave) and "anoa" (an Indonesian ox)—what new-school constructors call "crosswordese." Shortz, then the editor of Games magazine, took over the Times puzzle in 1993, bringing with him a sensibility that prized wordplay over obscure vocabulary. As the film's director, Patrick Creadon, puts it, "the old-school puzzles were more of a test, and the new-school puzzles are more of a game."

Although Shortz may throw in a few 10-cent words late in the week (the puzzles grow harder Monday to Saturday, with Sundays fixed around the midpoint), his favorite clues are those that require several areas of the brain to solve. Take this example, from a recent Times Saturday. Five letters, "Biggest part of a belt?" "Buckle," of course, doesn't fit, and how many other parts does a belt have? The answer, it turns out, is "Ceres," the largest rock in the asteroid belt. Getting the answer, Shortz explains, requires not only knowledge, but the ability to look past the obvious interpretation of the clue (a step hinted at by the final question mark). "You have to have a good vocabulary, know a lot of information, be a good speller, and have a good sense of humor, but the most important thing is mental flexibility," Shortz says. "To be able to take a clue and see the multiple ways it can be interpreted, and see which of them works with the crossing." If you think of "board meetings" as a place where boards meet, it's much easier to think of a four-letter word for what holds them there. "In the new school," Reagle adds, "the way you make a puzzle difficult is the answer's always easy, and the clue is always hard."

What differentiates crossword-makers of the Shortz/Reagle school from their knuckle-rapping predecessors is a love of language as it's used. The dirty secret of crossword construction is that the answers tend to be drawn from a fairly small pool; even the obscurities, generally short, vowel-heavy words like "ogee," "Omoo" and "Esai," recur frequently enough that you can pick them up in a matter of months. What gets Reagle jazzed isn't poking around the cobwebbed corners of the OED, but new ways of cluing familiar answers. He cites a recent favorite, "Leadfoot's comeuppance," leading to the fairly unexceptional answer, "tickets." "That's just an incredibly great, colorful clue," he enthuses. "It's amazing how people can come up with brand new, contemporary clues for the same old thing."

Not surprisingly, both Shortz and Reagle are word guys. Reagle recalls making rudimentary puzzles with the names of his first-grade classmates, while Shortz says the presence of black-and-white bathroom tiles helped clinch the purchase of his current house. That's not to say they're not susceptible to Sudoku; Shortz proclaims himself a regular solver, and Reagle says that the number-based puzzles are the perfect respite from a day of fitting letters into boxes. But ultimately, there's no substitute for a crossword, and the harder the better. "I like humor, I like standup comics, and I like making puzzles that are funny," Reagle says. "But I don't like solving them. I like a hard Saturday puzzle. I hate funny puzzles. All I can think about is how I should've made them. I'm happy to make funny puzzles for everybody else, but don't give me any."

Wordplay is now playing at Ritz Five.