Lunchtime at suburban Thomas Jefferson Middle School, outside Washington, D.C. Cup of french fries? Check. Mini-carton of chocolate milk? Check. Small plastic tiles embossed with dragons and flowers?

Check?

For one group of sixth-graders, the game of mah-jongg is so cool that they give up their lunch period to play it. They are about half a century younger than typical players of the ancient Chinese game, which resembles gin rummy but is much more complex. But they are as enthusiastic as if they had invented it themselves.

"Who's going to be with who?" they asked as they chose teammates and sat around a table in the classroom of Sandy Tevelin, who introduced them to the game (pronounced MAH-zhahn) early in the school year.

"I'll be with Maddy," said Lauren Montana, 11, one of seven students playing that day.

Then the game began, and their sentences started to contain such words as "Bam" and "Dot" and "Crack" — that's mah-jonggese.

Tevelin watched, smiling. For a dozen years, she has been offering her sixth-graders the chance to learn the game that in the United States is more commonly associated with Chinese or Jewish women of a certain age. Some years, there are no takers. But every few years, there will be a group of sixth-graders for whom the game clicks.

And sticks. Some former students, now college juniors, come back to play with Tevelin. And, as she reminds her students, it's an activity they can do for the rest of their lives.

"I ask them, 'When you're 40, are you going to want to play UNO? Are you going to want to play Connect Four?' And they say, 'Ooh, no.' But they're going to want to play mah-jongg, because it's ... a grown-up game."

The game, in which the students try to build a winning hand using 13 tiles they are dealt or trade for others, involves a lot of skill and strategy and memorization of rules. Tevelin introduced the rules incrementally, adding a new one every few days until the students absorbed them all.

After the food, the game heated up. Tiles clacked on the table as the students answered questions about why they decided to learn to play.

"Well, she told us the story about the original people who play mah-jongg," said Gino Rodriguez, 11, referring to Tevelin's earlier cohorts.

"It sounded interesting, and she showed us the tiles and then we decided to play," said Glenn Kinsman, 12. "And then people from other classes started coming."

Tevelin herself at first did not learn the game that her grandmother and mother played. "At the pool in the summer, we swam and all the mothers played mah-jongg," she said. "I remember, as a child, listening to the clickety-clack of the tiles on the table." She learned about 20 years ago and is now in a regular mah-jongg group.

Besides being something they can continue through their lives, she said, the game is a good ice-breaker for sixth-graders just entering the school.

"Two girls who for the first part of the year did not say a word to anybody, mah-jongg has given them a voice," she said. "Kids who did not talk before are talking now. Kids who were not friends before got to know each other because of mah-jongg."

Tevelin has shown them her grandmother's set, a worn snakeskin case containing yellowed tiles. Several students have found their own sets on e-Bay.

Gino's grandmother played in the Philippines. But some had never tried it.

"It was kind of hard to teach them," said Brooke Rippy, 12.

"My dad still can't pronounce it," Glenn added.

Melvin Argueta, 11, said that his sister, who is 16, likes the fact that he plays, because "I can finally do something that she can't."

The game ended abruptly.

"We call!" cried Maddy Brehaut, 12. "Mah-jongg!"

The others assessed how close they'd been. Brooke displayed her team's tiles, an assortment of colors and designs that had not won but evinced a certain elegance.

"We went for the prettiest hands," she joked.