Washington ? I came out to George Mason University’s Fairfax, Va., campus to luxuriate in Final Four frenzy. First thing I needed was a map.

Not to find the right buildings – the campus signage is just fine. No, if you want to get all academic and fancy about it, what I needed was an ethnographic map.

See, Mason, aside from being the home of America’s new darling, the Patriots basketball team, is the most diverse college campus in the land, according to one highly touted survey. Students come from 140 countries and speak 85 languages.

Every student I spoke to was happy to sketch out the turf for me. Abbie Redmon, managing editor of the Broadside, the student newspaper, directed me to the Johnson Center, the main student hangout, where the third floor is the Middle Eastern students’ spot and the second floor is where the Asians gather. There’s a place on the main floor where the fraternity and sorority kids – mostly white or black – fraternize and sororitize.

All over campus, people pointed out hangouts: That breezeway over there? Vietnamese kids. That corner of the lunchroom? Latino students.

The diversity imperative that has been so thoroughly infused into American education tells us that mixing with people of many different backgrounds is wonderful because it opens our minds and challenges our assumptions. Fair enough, except that as anyone who’s been to high school or college in the past generation can tell you, we tend to stick to our own, no matter what group we may be a part of.

George Mason, like pretty much all schools these days, caters to this tendency by supporting all manner of ethnic and religious affinity groups. Student fees help out 17 ethnic organizations, from the Bengali Patriots to the Persian Club to the Nepalese Students Association.

Add the fact that a large majority of Mason students are commuters, and you end up with a school that hasn’t developed a whole lot of social mixing or student spirit. Until this week.

Jai Lewis, the Patriots’ star center, gamely tried to make his way to his usual lunch spot Tuesday and quickly gave up. He was stopped at every step, signing dozens of autographs, on shirts, caps, textbooks, even on other students’ ID cards.

“Usually, I walk through here, no problems,” the 6-7 senior said. No more. He was loving every second of his newfound celebrity, but he did note that although he’d been in classes with some of them, he’d never actually spoken to any of the students now peppering him with autograph requests.

“People really stick to their own ethnicities around here. But right now, everybody’s coming together to have fun,” Lewis said. “Hopefully, that will stick.”

Furhan Qureshi watched Lewis signing autographs and kicked at the floor. “Man, I had English class with three guys on the team, and I never spoke to them. Now I wish I had.”

Qureshi, a junior and an officer of the Pakistani Students Association, took me to his usual table – on the third floor, of course – where several other Pakistanis were studying. “From a sociological perspective, people tend to go with their own kind,” Qureshi said. “It’s a hassle to get to know anyone outside your group at Mason. The frats are very divisive; they already have all their friends. Most of the foreign students are commuters; we’re either studying or driving. No time to just hang out.”

But Qureshi, his friend Farhan Khan and a bunch of other Pakistanis went to last Sunday’s game against Connecticut and found themselves shouting soccer chants with students from Turkey – in Turkish. “I wouldn’t usually hang out with them, but there I was, jumping on their backs,” said Khan, who painted his beard green and gold for the occasion. “I like their flag, too.”

The Patriots’ game against Connecticut brought together Pakistanis and other Muslims from countries that don’t share a language. Pretty soon, Qureshi and students from a slew of different lands were chanting “Mason zindabad!” – Farsi for “Long live Mason,” which was as close as they could get to “Go Mason!”

No one I spoke to thought the school’s NCAA tournament success would erase the cultural divides that make Mason such a Balkanized campus. But nearly all found themselves this week reveling in the Patriots’ triumph with students they’d never before bothered to notice.

“There is so much division here,” says Redmon, the student newspaper editor, “but we’re hoping people will start to look at Mason as just one Mason and not commuter Mason and ethnic Mason and all those different Masons.”

The line for Final Four T-shirts at the bookstore was 368 people long when I left campus. Along the queue, I heard conversations in 11 languages. The word that kept popping out was “Mason.”