Summertime is the season when even workaholics can't resist taking a little time out to play, whether at summer homes or in town. Some Washingtonians cope with pressure-filled lives by creating play places in year-round houses that provide a place to exercise to relieve tension or add a bit of whimsy or fantasy to make life a little fuller. For those who want the best of both worlds, the old "rec room" with a wobbly ping pong table is not enough.

Backyard pools and tennis courts are now almost a cliche among a certain set of Washington area homeowners in places like Potomac and Great Falls. But some pocketbooks and imaginations go beyond the now commonplace home pool to houses boasting more unusual features -- like train tracks running around the property of several "live steam" model rrailroad buffs, a fireman's pole in a Georgetown living room and a private golf course surrounding a Potomac home.

For a Bethesda builder who prefers anonymity, happiness is never having to say "fore." As one who takes his hobby seriously, this avid golfer hired a professional golf course designer to create a course for his 12-acre estate. The result is an 18-hole course cleverly squeezed out of three separate holes, each of which can be played six different ways, "so it won't get boring."

What if a wayward golf ball should wend its way into a bedroom window? "No problem," replies the imaginative builder, "we used bullet-proof glass on all the windows."

A similar desire to pursue a sport drove architect/developer Richard Colby and his colleague Richard Compton to build Colby's home around his private tennis court.

In fact, one wall of the house was specially designed with extra resiliency as a backboard for practice shots, and all the nearby windows are thoughtfully made of tempered glass. Colby is in the process of building himself a new house at the edge of a new play place -- a man-made lake just down the road from his current home -- now on the market for a mere $379,000.

In yet another area of Great Falls, architect Ron Taylor of Leigh Mill Associates built a series of contemporary homes and sold them to people before completion so that special custom features could be included to suit individual owners' needs. This flexibility enabled a Northern Virginia couple to put a racquetball court, instead of the traditional recreation room, into their ground floor. The court, four-fifths the size of a regulation court, was made possible by simply digging down a little deeper than ground level to achieve the necessary high ceiling for the sport. Now that the husband's leading racquetball partner, his son, is off at college, the house and court are a little too much space for the couple's needs and it too is for sale for under $300,000.

But there's more to designing a house for play than mere sport -- witness real estate entrepreneur Sam Pardoe's elegant Georgetown home. To live out his boyhood dream of being a fireman, Pardoe installed his own personal brass firepole on the third floor. Open a Dutch door with a shiny brass knob and step into childhood -- a smooth, fast trip right into the living room. As if this bit of whimsy weren't enough, Pardoe has transformed his living room into a private disco that includes 48 speakers and 32 colored lights. And if that's not enough, Pardoe has a model train track running around the circumference of his wood-paneled library.

But the real model train buff's wonderland is John Armstrong's Silver Spring basement. "Not exactly the kind of thing you take down the day after Christmas," says the would-be railroad tycoon of the 1,100 feet of track snaking in and out of pipes and around the 24' x 36' room. Running at eye level is the Cannandaigua Southern Railroad -- an O-gauge line (1/4 inch to the foot scale) model railroad layout, complete with a roundhouse complex and a map of would-be connections with better-known lines. The vintage '50s line of over 200 cars (which can be operated by as many as 10 people) is so complicated that Armstrong has a chart to keep track of the movements of his freight cars on the line.

Unlike most hobbyists, Armstrong has managed to parlay his play into a living. After some 25 years as a mechanical engineer, he now serves as the Washington editor of Railway Age magazine, a journal for real railroaders. In addition he is the author of a book explaining the workings of a rail system for railroad employees and has written a definitive booklet on track planning for realistic operation of model railroads.

Although there are times when Armstrong's world seemingly loses the distinction between fantasy and reality, he keeps it all in perspective by a tongue-in-cheek approach. His magnificant miniature duplicate of the Point of Rocks, Md., Victorian rail station is appropriately dubbed "Warm River Station," in honor of its proximity to Armstrong's basement hot water heater. s