MY KIDS HAVE yet to come across a play structure they don't like, but their favorite by far is the new one at Cabin John Regional Park in Rockville.

Appropriately named Action Playland, it was built, says the landscape architect who designed it, "to really give kids some exercise."

That it does. Heidi Sussman's state-of-the-art play structure, recently added to the park's older playground, is an elaborate obstacle course that covers more than half an acre of wooded, sloped and terraced ground. Children typically stand in awe of the structure for a few moments -- before running over and leaping onto it.

Sussman, like most of today's playground designers, considered the needs of children of all ages and skills. Toddlers just learning to stay on their feet will find plenty to do on the ground: Steering wheels, steps, tires and plastic tubes keep them busy -- and out of the way of older children. For preschoolers, there are low walls, vertical climbing tubes and ladders to take them to comfortable heights for play.

Older children, definitely ready for a tougher physical challenge, like the 40-foot net tunnel, the 30-foot tire bridge and the 50-foot tunnel slide, which requires scaling a wall of tires or an incline of clattering planks to reach it. And, although in general this is not an accessible play structure, special-needs kids will be able to manuever wheelchairs into a roomy play gazebo and onto a level area to reach rings and hand-over-hand ladders.

While most children like the structure for the workout it gives them, some will seek within it quieter places for less physical play. The terraced mounds, the tree house deck and mounted steering wheels, for example, are designed for that purpose. (This play structure can get very crowded, but it's pretty peaceful on weekdays, early Saturday or Sunday and on sunny mid-winter days.)

For parents, the wooden terrace beams and benches provide places to sit, but unless your kids are independent climbers, you probably won't be sitting down much. (And if your kids are independent climbers, you'll probably be on your feet trying to keep track of them.)

What I like about this play structure is the way it feels like part of the woods. Sussman selected wood materials to give the structure a tree-house feel and built some of the structure to wrap around existing trees. A tree-saving construction plan restricted access for heavy equipment, and special systems were installed to supply air to tree roots buried by extensive terracing.

Virtually all play structures being put up these days are constructed of pre-fab modular units custom-fit to the site, and Action Playland in Cabin John is no exception. Sussman, who liked mazes and obstacle courses as a child, met on the site with Children's Playgrounds, the manufacturer, to decide on the best equipment choices and combinations.

Before construction could begin, the playground plans had to go through other reviews: one before the public, another before county architects, engineers and horticulturalists who offered ideas and suggestions.

After the playground was built, Sussman spent another couple of months observing kids at play -- then modifying the equipment for safety. (A high platform was caged in, age limit signs were added and swings were moved out of traffic patterns, for example.) The entire process, from its initial conception to completion, took about two years and cost $200,000. Sussman is now working on the playground design for Maryland's Wheaton Regional Park.

Children will probably want to stay on the new equipment on the first visit or two, but after awhile they'll be more apt to explore. Adjacent to this new structure is the original playground, put in just after the park opened in the late '60s, and slowly filling up with new play pieces as the old ones wear out.

Covering 548 acres, Cabin John also has an ice skating rink, a zoo, hiking trails, sports fields, indoor and outdoor tennis courts, picnic tables and pavilions, a separate tot lot, a nature center, campsites, and, from April through September, a train.

It's a good place to spend a day -- or an action-packed hour.

CABIN JOHN REGIONAL PARK -- 7400 Tuckerman Lane, Rockville. 301/299-4555. Open year-round from sunrise to sunset. The ice rink is open November through March; call 301/356-2246.

Here's what's new in other area play structures:


KEENE RECREATION CENTER -- Riggs Road and Rock Creek Church Road NE. 202/576-7682. This brand-new schoolyard playground has a compact but challenging toddler climber and a separate more spacious play area for older kids. Squares of rubberized padding under all the equipment and a fenced-in lot make this a safe place.

RANDALL PARK AND RECREATION CENTER -- South Capitol and I streets SW. 202/727-5505. Kids can look at the Capitol building while they dig in the sand or play on all the swings, slides, decks and tunnels on these brightly colored metal climbers. Kids call this the Pepsi Park because the equipment was donated by the Pepsi-Cola Company.


CARROLLTON ELEMENTARY SCHOOL -- 8300 Quintana St. (at Westbrook Drive and 84th Street), New Carrollton. 301/577-6140. New York architect Robert Leathers custom-designed this expansive wooden fort structure for the schoolyard site. Kids like the turreted towers and all the different levels.

ELLSWORTH URBAN PARK -- 621 Ellsworth Dr., Silver Spring. 301/495-2546. Right next door to the Silver Spring Library, this nicely landscaped playground has a colorful structure with lots of slides, and a creative wood block arrangement that everyone climbs on.

MARTIN LUTHER KING JR. PARK -- 1120 Jackson Rd., Silver Spring. 301/622-1193. This structure has a variety of climbing surfaces to tackle, including one of those orange roller-bar slides that kids love playing on. Wheelchairs can roll up and into this structure and it's at the right height for supervising adults to reach in and lend kids a hand.


BORGE STREET PARK -- 33 Borge St., Oakton. 703/246-5700. Though small, this playground has a good sampling of what goes into parks today: colorful monkey bars that twist instead of going straight across, a deck structure with plastic tunnels and turning slides, traditional swings, an on-the-ground balance beam, a small wooden block structure for sitting or climbing on -- and lots of open space for running around.

LYON VILLAGE PARK -- 1800 N. Highland St., Arlington. 703/358-3322. Swings, slides, ramps and a corkscrew fire pole keep kids busy here. On a smaller scale are a toddler structure and two red doghouse-sized playhouses.

RESTON NORTH PARK -- 1635 Reston Pkwy., Reston. 703/246-5700. Kids like the small bridge that leads from the parking lot to the play structure. A toddler climber and baby swings are separate from a more advanced climber with many decks, ramps and various mounted metal bars that kids can sit on, swing form and climb over. Spacious mulched terraces are great for tag.

Susan Glick last wrote for Weekend about Maryland's Susquehanna State Park.