Matt Gaffney knows why people like puzzles: “The world is complex—there are a lot of moving parts. With crosswords, there’s only one right way.”

As for himself, Gaffney—author of The Washingtonian’s monthly crossword and of the new book Gridlock: Crossword Puzzles and the Mad Geniuses Who Create Them —says, “I just enjoy them.”

Word puzzles and other forms of “mental calisthenics” are more popular than ever. Witness the popularity of the number puzzle sudoku and of Wordplay, the documentary about New York Times puzzle editor Will Shortz and other crossword aficionados.

These pastimes—whether done for fun or competitively—have another plus: Research suggests they can help protect the brain against Alzheimer’s and other degenerative diseases.

Newspapers are a good place to start enjoying crosswords or sudoku. Puzzles in the New York Times get harder as the week goes on; Gaffney advises that you not dive into your first one on a Friday.

If you get so into it that one a day isn’t enough, buy a book of puzzles. Shortz has edited many, including The New York Times Ultimate Crossword Omnibus and the Sudoku: Easy to Hard series.

Scrabble is another way to indulge a puzzle passion. If you want to take it beyond casual matches with family or friends, check out the National Scrabble Association’s Web site (scrabble-assoc.com) , where you’ll find local Scrabble clubs such as a one codirected by Ted Gest (dcsclub.info) .

Every Tuesday from 5:30 to 10 pm, Gest and company meet at the Chevy Chase Community Center (5601 Connecticut Ave., NW). Although members of his group, Club 171, include Stefan Fatsis—author of Word Freak: Heartbreak, Triumph, Genius, and Obsession in the World of Competitive Scrabble Players —Gest says people shouldn’t be intimidated: “We try to match people up by level of ability. We’re not trying to get people to beat up on each other.”

To hone your skills between Tuesday matches, the Internet Scrabble Club (isc.ro) has lots of members looking for a game. And Everything Scrabble —cowritten by three-time national champion Joe Edley—has exercise puzzles, strategies, and ways to make friends with the letter Q.

—Caleb Hannan