TUCKED SNUGLY between the Reflecting Pool and the Ash Woods that surround the D.C. War Memorial, the Washington Area Frisbee Club privately practices the game it calls Ultimate.

After years of turf wars with the Mall's soccer and softball participants, the area flying disc enthusiasts are now comfortably ensconced on the JFK Memorial Hockey Fields, where they may occasionally attract the curiosity of passersby but are spared the interruption of bouncing balls.

The group's secluded habitat belies the openness of the organization. Not only has the WAFC issued a blanket invitation to men or women of any age or Frisbee experience to join its coed summer league, but free instruction is also promised to anyone who desires it.

"People need to have enthusiasm and like to run around. That's the only prerequisite," says Eric Simon, president of the 420-member WAFC, now in its 10th year. "The purpose of the summer league is to provide recreation to the Frisbee player and to teach new people the sport."

"I can teach anyone to throw a Frisbee in a day," says Sue Wallace, a researcher who met Simon playing Frisbee in April 1984 (and married him last weekend). "You need to know two throws, the backhand and the sidearm throw. Some people use an overhead which flies upside down. In terms of summer league, there's always someone to show someone what to do. It's not that hard. After that, it's up to them to practice it."

Above each of the three fields, marked only by small orange cones, a Frisbee floats lazily above the competitors who chase it wildly during rapidly paced games where the players yearn to achieve the ultimate in Ultimate, which is to "get ho" -- short for getting horizontal or making a diving catch.

Washington's summer league, which commenced its fifth season two weeks ago, is believed to have been the nation's largest in 1986, with 380 participants -- most of whom are serious about having fun.

"The public thinks we're a lot of people with long hair and bare feet tossing a disc around, but as you can see, we wear cleats and we take our sport very seriously," says Simon, who also captains a team called X. "I'm a lawyer working for the government. We have three engineers on my team. The person who wants to play Frisbee wants to run around a lot, wants to meet new people, wants to play hard, but not in an overly competitive atmosphere. Many people play because of the social aspect."

"Say 'Frisbee' to the general public and people immediately think beach, long hair and dogs," agrees Gary McGivney, national director of the 4,200-member Ultimate Players Association in Greenwich, Connecticut. "When you say, 'No, it's a sport,' people's faces go blank. But once they see the sport, they can't believe how beautiful and how demanding it is. They watch it, play it and then love it."

Ultimate Frisbee was created in 1971 by the student council of Columbia High School in Maplewood, New Jersey. In the first Ultimate contest, Columbia defeated Millburn High School. The following year, the first collegiate contest was played, with Rutgers downing Princeton, 29-27. There are Frisbee clubs on approximately 150 college campuses, McGivney says, and the first national high-school championship will be staged in 1988.

"Up to now, Ultimate has not been a very significant factor in our sales," says Dan Roddick, head of sports promotions for discmaker Wham-O -- and the most valuable player in Rutgers' 1972 victory over Princeton. "But we count it as very exciting . . . In the next five years, there will be a Frisbee club on every {college} campus in the nation and the high schools won't be far behind."

Roddick estimates his company has sold 100 million Frisbees in 30 years of production, though "our archivists have not been very accurate and we have no count on how many are currently on people's roofs."

Ultimate is an easy game to follow, despite its disdain for two mainstays of American sport: clocks and referees. Games are played on fields 120 yards long and 40 yards wide with seven players per side. On either end of the field is an end zone 25 yards deep where points are scored. Teams advance the disc with passes. When a pass is caught, the receiver has two steps in which to stop and then must keep one foot planted while attempting to pass to another teammate. A pass completed in the end zone scores a point. If a pass is not completed or is knocked down by a defender, possession goes to the defenders. Only incidental contact is allowed.

Matches are usually played to 17, 19 or 21 points. The rules are enforced by the "spirit of the game," where players make their own calls. If the players cannot resolve a dispute, the team captains try. In the rare instance when an agreement still can't be reached, possession reverts to the last thrower. Recently, major competitions have employed teams of four "observers" to decide unresolved conflicts (can referees be far behind?).

People may come slow to Ultimate Frisbee, but they tend to stay with it. There are currently four men's and two women's teams in Washington that spend as many as 20 weekends a year traveling the country for competitions. Yo Mama recently captured the men's title at the Mid-Atlantic Regional Championships in Newark, Delaware, with Just Say No placing third and X finishing seventh. Cool Mama Seven took second and Land Sharks, captained by Wallace, third on the women's side. The following week, in the Eastern Championships in Amherst, Massachusetts, Cool Mama Seven advanced to the quarterfinals before losing.

"I've been playing for two years and it's become a major part of my life," says Marie Hartley, a massage therapist and captain of Cool Mama Seven. "When I first started playing, I really didn't know many people. Now it's become my social life as well as my hobby. A lot of my good friends are from the Frisbee circle. You like to be outdoors, you like physical activity. Then, often it turns out you like the same music. There is a similar enjoyment of life. Why sit at home when you can go out and play Frisbee?"

"It's addicting," Simon says. "It involves so much physical exertion and so much dedication. Another part is the social aspect. It's like a big family. It's small and that makes everybody close. And with the spirit of the game, it discourages people who can't {reach agreements with others}. We're a very homogenous group."

Summer league play continues through mid-August with games played all weeknights and weekend afternoons. There's also non-team play Wednesday nights and Sunday afternoons. Teams in advanced and amateur divisions play approximately three games every two weeks, Simon says, with a $3 fee charged to each advanced player ($2 to each amateur). Membership in the national UPA costs $7.

The league finishes with a two-day tournament August 15-16 for which all teams are eligible. Simon says new players will be accepted even though league play has begun.

"Summer league is incredibly laid-back. A lot of people were encouraging and people were always helpful," says Miriam Goodman, a cell biologist who joined the summer league last year after playing at Brown University and while attending Whitman High School in Bethesda. "Most of the socializing I did last summer was done with people from Frisbee. There were a lot of people on my team who had never played before and while we didn't do real well, we had a great time. Even if somebody's never played before, people will still throw him the Frisbee. In a sport like soccer, people who have never played never see the ball." THE ULTIMATE EXPERIENCE --

For information and summer league applications, call 548-3479 or show up at the fields.

THE UNOFFICIAL EXPERIENCE --

For those who love Frisbee but fear commitment, D.C.'s floating Ultimate game, called SMUT (short for Smithsonian Museum Ultimate Team, though it is not affiliated with the Institutes) is suggested. This "amalgam," described as "anti-organization" by one prominent member, operates within the shadow of the Washington Monument on the Smithsonian side, often on the green between 14th and 15th streets NW. It is suggested only experienced players attend for SMUT's summer hours, which are Tuesday and Thursday at 6 p.m. and Saturday and Sunday at 5 p.m.