For weeks, the Kovanic family has been busy transforming its McLean home into a winter wonderland.

A gaggle of illuminated Santas line the walk to the front door. Inside, a Christmas tree with White House ornaments sits on a hall table. The downstairs bathroom features a carousel that plays 23 seasonal songs. But the holiday tour de force is an intricate display set up in the family room.

Carefully arrayed on a plywood platform covered with Styrofoam sculpted to resemble alpine mountains lies a festive, wintry holiday scene. More than 80 miniature houses--including a ski chalet, several churches and a movie theater--dot the landscape while ice skaters twirl on two ponds and skiers conquer the papier-mache slopes.

A coal-black Lionel train chugs through a mountain underpass while Santa flies on his reindeer-led sleigh overhead. Every inch of space is smothered with quaint buildings, Disney or holiday figurines, Christmas trees and bridges that straddle waterfalls. There's even a tram that toddles up and down the mountain and a trio of fiber-optic fireworks complete with sound effects. A polar bear trucks letters to Santa in a red cart while poinsettias perch in their own little hothouse.

When night falls on the display, which fits snugly into a corner of the cozy room, it glitters with lights underneath a makeshift sky studded with glowing blue stars.

"Don't you think it's kind of magical?" asked Joan Kovanic, 66, who has lived in the house for 30 years with her husband, Francis, 74, a retired naval aviator.

The Kovanics always dress up their home for the holidays--their house boasts at least six decorated Christmas trees of varying sizes--but the elaborate wintry village scene began only six years ago and has grown each year. "You'd think kids live in this house the way they decorate," said Kim Lawler, 42, of Falls Church, one of the Kovanics' four grown children.

Francis is the brains behind the display, masterminding the electrical circuits so fuses don't blow and making everything mechanical work smoothly. Kim is the creative genius, deciding where all the houses and objects should be placed, adding glitter to the mountains and transforming cotton balls into snowdrifts. Joan acts as the brake in this family production, telling them when to stop.

If it was up to Kim and her father, the display might take over the entire room. "She's the gong," Kim said of her mom.

Almost every Saturday during the year, the Lawlers and elder Kovanics attend evening services at St. Luke's Catholic Church in McLean and then go out to eat. Come early summer, the dinner conversation turns to plotting the display, and the installation begins in August. Francis builds the platforms during the day, and Kim pops by in the evenings to decorate, often towing her husband, Mike, and their 10-month-old daughter, Sarah.

Though the work is tedious, Kim said, she stays for hours. "He'd have to kick me out," she said of her father. "I'd want to keep working."

This year Kim's sister Candy Bendall, 44, of Round Hill, who used to try to compete with her father for best holiday light decorations, helped out, too. Their brother, Frank Kovanic, 38, of Leesburg, occasionally stops by with his dog, Charley, to put in his two cents. Only their sister Heidi Preston, 40, who lives in South Dakota with her husband and two sons, is left out. But she visits every other year to ooh and aah over the hard work.

With different members of the family so invested in the same project, some tension usually crops up, often over work habits: Francis tends to be neat while Kim is messy. "There's always a couple of good fights," Kim said. "This year was pretty good because I cooperated."

Still, she's in awe of her father's technical ability to make the display work. "He could do it without me," she said, "but I couldn't do it without him."

Watching her father help her daughter with the train controls, Kim added, "I think he really does this for the kids."

"He's just a big kid at heart," her brother chimed in.

The elder Kovanic looked up from the train and nodded at his granddaughter. "Just watching her smile and all, that's worth" the effort, he said.

It all started when Kim began collecting Department 56 items--miniature houses and village scenes--which come in themed sets such as "Christmas in the City" and "North Pole." She didn't have room for them in her home so she brought the items to her parents' house, thinking they would wind up displayed under a tree. But her father was so taken with the petite buildings, street lamps and other set pieces that he decided to build a platform to show them off. As Kim added to her collection, now worth about $20,000, the platforms grew. This year, about 20 houses didn't make it into the display because they ran out of room.

Everything stays up until early February, which is fine with Joan, who despite being "the gong" loves the creation. "I could live like this all year, and then I don't have to clean," she said. Francis has the unenviable job of packing up the items in the right boxes and ferrying them to their storage spots. The "basement looks like a gift shop," Kim said.

Only after everything is safely put away does her father focus on how much effort the project takes, in addition to the family's multitude of other indoor and outdoor Christmas decorations. "I keep threatening not to do this every year," said Francis, flashing a wry smile.

"But he'll keep doing it, because we all get excited come platform time in August," Kim added.

After all, for the Kovanic family, creating the magical display is the ideal Christmas present to give to one another: togetherness.

CAPTION: The Kovanic family--granddaughter Sarah Lawler, 10 months, daughter Kim Lawler, Joan and Francis Kovanic and their son, Frank--admire the vast miniature Christmas village in the family room of their McLean home. The extended family begins to build the project each August, and it stays in place until February.

CAPTION: Figures of children skate on one of the two ponds that dot the miniature landscape.