Off Rte. 50 and Glebe Road, on 26 acres in themidst of the Washington area's most densely populated county, sits the sprawling, 235,000-square-foot Thomas Jefferson Community Center, home away from home for thousands of Arlington residents and a standout facility in an area that has spawned some of the finest recreational programs in the nation.

The center's air-conditioned, 1 1/2-acre gymnasium is one of the largest on the East Coast, housing a six-lane, one-eighth mile track and 11 basketball courts of various sizes. Outside are two soccer fields, a half-mile fitness trail, two softball fields, four tennis courts, two basketball courts and a "tot lot" where children can play. Most of the outdoor facilities are equipped with lights for night use.

On a busy night, 600 people pack more than 40 programs at the center, including weight lifting, volleyball, pottery, photography, basketball, fitness classes, woodworking, theater and an endless choice of planned activities for participants ranging from toddlers to senior citizens. Over a year's time, 350,000 people come to the center they affectionately call "T.J." for the price of $20 a year if they live in Arlington and $85 if they don't.

While it was T.J.'s sharing of its facilities with an intermediate school that originally earned it a national reputation, the center has since become recognized for ambitious community events including a triathlon, bike race and body building contest. And many of those involved say the people -- from committed, talented instructors to determined participants -- are the key ingredients in the high-calibre programs and pep-rally style morale.

"Every day there is the excitement of the whole range of ages and segments of the community," said Constance McAdam, director of the Arlington County Recreation Division. "They come from low-income and high-income backgrounds, people with physical handicaps alongside people who don't speak much English."

The center's namesake, egalitarian President Thomas Jefferson, would have been proud.

For 17-year-old Cambodian refugee Leng (Larry) Kouch, T.J. has provided a place to meet others from his homeland, as well as teen-agers from around the world. Kouch, who has learned to use all the exercise equipment and play both basketball and volleyball, looks forward to Friday afternoons when youths from across the county gather at the center.

LaVon Hartman, now an accomplished potter, has used the pottery studio experience to overcome personal trauma. "Anything that helps us integrate parts of ourselves is positive," she said, referring to the therapeutic value of making clay into ceramics. "That's the kind of attitude I see here at the center. I come in and I feel welcome. It makes you want to come back."

District resident Michael Torrence pays a $5 day fee to use the gym and the photo lab. "It's good because you can kill two birds with one stone," he said. "I can play basketball and process film."

Richard Long took a woodworking class and now makes tables in the woodworking shop during open studio hours. "You can always take classes, but then you're expected to buy your own equipment. I've traveled all over the country and nowhere provides this kind of service."

Most entering the Thomas Jefferson Community Center on S. Second Street head in one of two directions, to the football field-sized gym or to the super-equipped art studios. Others, such as senior citizens, may go to classrooms for meetings. And some people may attend or perform in the theater.

The gym, just refinished with a hard, rubberlike flooring to cut down on injuries, is generally brimming with body builders on the weight machines, volleyball or basketball players on the courts, runners on the track, and exercise classes or tumbling athletes on bright blue mats. Special fitness clinics are offered in the fall.

The art studios accommodate classes in jewelry making, pottery, woodworking and both color and black and white photography.

When classes aren't in session, the cement-floored space is likely to be filled with amateur artists who pay a nominal fee to use the materials and darkrooms.

One- to three-day workshops in such specialized crafts as Japanese raku ware (a type of pottery) or southwestern Indian pottery -- fired outdoors in primitive, hand-built kilns -- are held throughout the year.

A staff of up to 40 paid and 20 volunteer workers, largely from Arlington, boasts specialized educations (such as the master of fine arts degree held by the studio aide) and has an average of five years experience at T.J.

Instructors are available from opening to closing (9 a.m. to 10 p.m. now, 6 a.m. to 10 p.m. during peak winter months) to help members, whether in turning clay on a pottery wheel or turning flips on parallel bars.

"We encourage a positive attitude toward people and differences," said Toni Hubbard, the center's director, who has worked at T.J. since it opened in October 1972.

Those who run the center said they take special pride in offering more than the average public recreation program. Laura Lazour, one of two assistants to the director, said, "Our philosophy is to offer the highest quality, most innovative event we can at a community level. We want to have state-of-the-art art programs and be on the upswing of fitness trends."

The idea for T.J. was spawned more than 13 years ago, when Constance McAdam and other county leaders returned from a cross-country tour of community centers and opened the doors on this region's first joint-use facility.

The mammoth structure houses Thomas Jefferson Intermediate School as well as the community center and was designed with the notion that shared space and costs can improve operating efficiency.

All indoor operations costs are paid under the school's aegis, while the parks department covers outdoor maintenance of fields and courts.

"It's a recognized example of more efficient use of taxpayers' money to meet a diversity of public needs," said Barry Tindall, director of public affairs for the National Recreation and Park Association.

Tindall, whose office is in Northern Virginia, said he often takes international park policy makers on tours of T.J. as "an example of creative thinking and practical investment of public resources."

Although she admits maintenance of the aging center could be improved, McAdam pronounced the programs "an exceptional success" that have made T.J. a focal point for area residents.

She concluded: "It's where people grow and learn and change, and through their leisure pursuits and recreational activities keep vital and healthy."