Not only do old rugby players never seem to die, lots of them don't even have enough sense to quit. In the Washington area as around the country more and more "old boy" sides are sprouting like gray hairs.

To qualify as an old boy you have to be over 30 -- more usually 35 -- and still foolish enough to want to play the rough-and- tumble game of Rugby Union Football.

Locally there are four established senior sides: the Poltrooms, whose letterhead bears the motto, "Hostile, Fragile and Senile"; the FBI, a.k.a. the Foggy Bottom Irregulars; the Chesapeake Old Boys, whose symbol is a rocking chair; and the Montgomery Old Boys, the newest and youngest group, with other clubs occasionally able to resurrect enough veterans for a game.

Today through next week fine Old Boy Rugby will be on display with the visits to the D.C. area of two outstanding elderly foreign sides, Germany's Hamburg-St. Pauli team and the XL's from Toronto, led by bartender-priest Freddy Miller.

The Germans have an orgy of four games scheduled for their eight-day stay. Their nonstop round of play and parties will include games in Towson versus the visiting SL's, a well-to-do over 40s club that is flying down for the weekend, and their hosts, Chesapeake, whose president and benevolent dictator is "Big Dada" Bud Aldridge.

The rest of their itinerary includes a cocktail party and game with the FBI, wizened old George Washington Club players who still hang out at the G.W. Clubhouse on Capitol Hill and then the Poltroons (Webster calls a poltroon a spiritless coward), under the leadership of Ken "the Ancient Bugger" Wood and Gerry "Himself" Fenton. Hamburg will try to depart on the 17th.

Fenton, 49, a contractor, is considered by many to be the epitome of a rugby old boy, although he never was a "young boy." He started playing for the Washington Rugby Club in 1963 when already 30.

"He was a dominant player throughout the '60s," said Wood, his friend and teammate, "and a very useful player into the '70s." Wood, 44, who is in the legislative branch of EPA, added, "The best way to describe Gerry is that he's ebullient. Gerry's always looking at the lighter side of things, always has got a wisecrack, and loves rugby.

"He's toured Ireland, New Zealand, the Bahamas and been all over the U.S. with one side or another. At the Golden Oldies Tournament in Long Beach, California, he played in 13 games for 12 teams, including ones from Japan, Spain (the Latin Lovers), New Zealand and Canada."

Fenton, who gets around by big motorcycle and small private plane, said he started the Poltroons "because I felt Washington needed a prestige senior side to meet the challenge of the emerging circuit. We have a pool of about 50, with about half actually showing up for any particular game.

"I like Old Boy Rugby because we have skilled players who really know what they're doing but simply play at a lower key. You might say we play class rugby in slow motion. It just gets in your blood. I intend to play as long as I like -- heck, I've just got a new pair of boots and I'm certainly not going to quit until they wear out."

Wood hangs in because "I still get a kick out of the contact, in spite of the fact that my body is beginning to give out on me."

Tom Hartney, 39, a systems analyst and active member of the FBI, who also played for the Silver Hawks in San Jose, explains "It not only allows players to continue but also allows the older players to step aside gracefully and make room for the younger guys on the regular club. When I was in California, I actually played against a man who played for the U.S. in the Olympics."

Recently deceased Rudy Schola, who played key roles in the U.S. gold metal victories at the Olympics of 1920 in Antwerp and 1924 in Paris, was 82 when he played in his last match at Pebble Beach.

"It's more laid-back while still being competitive," said Rich Gunter, who owns a sports store and who at 32 is considered a young colt for the Montgomery Club. "We usually play three 20-minute periods instead of two 40-minute halves and allow freer substitution. That way everybody gets to play. It's just a more friendly brand of ball."

Which brings in the second reason for the growth of Old Boy Rugby: the social angle. Phil O'Brien, 35, vice-president of a music company and Montgomery teammate, agrees. "It's great to get your old friends back out on the pitch. In an old boys game everybody wins. Rugby guys love to reminisce and the old guys reminisce best."

"The movement has benefitted rugby in many ways," according to Sonny Judkins, 39, an insurance appraiser and Chesapeake stalwart. "Some of the old guys come back out and find out they still like to play. I've worked my way back onto our club's regular second team, for example. And more importantly, the more experienced guys are able to provide administrative and coaching leadership for their clubs.

"Old Boys is the wave of the future; pretty soon most clubs will have a senior side. Also with older, more established people, we find we can afford to tour more."

Going on tour is a very popular aspect of old boy rugby. Mike Scully, a 35-year-old expatriate Englishman and Poltroon, went to Europe with the FBI last year and helped arrange the Hamburgers' visit. "It's just great. Rugby is truly an international sport and I really appreciate the opportunity to meet and talk with other rugby fellows. Wherever you go, everything's always first class, and with old boys you don't have to prove anything. I mean we've all played before, you know. Now it's just for fun."

Other factors that keep the ''old boys" and their wives happy include no practice requirements and a schedule of only two to five games a season. "As we get more established in our communities our wants and values tend to be different," Fenton said.

"Our parties (a rugby tradition after every match), for example, aren't as wild. You might say we're more sedate both when we're playing and when we're partying. We just try to relax and keep going."

If you are an experienced rugby player over 30, and still foolish, call:

Poltroons -- Gerry Fenton, 656-1111, Ken Wood, 757-0548

Foggy Bottom Irregulars -- Tom Hartney, 840-7191

Chesapeake Old Boys -- Tommy Dee, 871- 1440, Bud Alridge, 337-7949

Montgomery Old Boys -- Phil O'Brien, 770- 2341, Rich Gunter, 258-5242