The Arlington County Fair, which opens for the 14th year tonight, is just a little different from the fairs to be found in the rolling hills or fruited plains of a less-developed county.

For one thing, parking near the fairgrounds at the Thomas Jefferson Community Center will be next to impossible.

But those who leave their cars behind and hop on a free shuttle bus to the fair today through Sunday will find many of the ingredients of any self-respecting county fair.

Some things, though, are missing. "Usually, with county fairs, you think about walking through the mud. That doesn't really happen here," said Robin Renner, one of 17 volunteers who organized the fair. "We're pretty much in the city, and here we are having a county fair."

There will be traditional blue-ribbon contests, carnival rides and a few farm animals to pet or ride. But the fair will also boast food stands stocked with Vietnamese, Mexican and other cuisines native to many Arlingtonians. Opening the festivities tonight, with a performance of ragtime and Dixieland music, will be the Environmental Protection Agency's Hazardous Wind Ensemble, a pickup band formed by government workers.

The theme for the 14th annual fair is "Gateway to the '90s."

"It's a good way to close summer out, get outside and see a lot of things. It's a good way to get information about where you live," said Renner. Renner estimates that 70,000 people will do just that.

Among new attractions will be a horseshoe contest and tournaments of chess and checkers on Saturday for adults 55 or older. The winners will represent the county at the state fair this fall. Also on Saturday, children ages 5 through 12 can participate in old-fashioned fair games organized by teenagers from Arlington's six 4-H clubs, including sack races, a pie-eating contest and three-legged races.

Pony rides are back after an absence of several years, with a different pony owner than in past years. Fair organizers had been dissatisfied with the previous pony owner's treatment of animals. Fairgoers seeking a more dizzying ride can take a whirl on a Ferris wheel, a merry-go-round or a handful of other carnival rides.

Bold county residents who claim to bake the best wedding cake, candy or other goodies will cater to the judges in the baked goods contest, one of about a dozen blue-ribbon competitions that draw hundreds of entries each year. The judges will also award ribbons in several age categories for the finest honey, food preserves, needlework, clothing, crafts, visual artworks, photography, garden produce, flower arrangements, ceramics and dolls.

Between rides and numerous musical shows, including a show by Arlington's senior adult performing group, the Merrymakers, fairgoers can wander the roughly 300 vending stands in search of unusual wares. Most vendors will be commercial, with products ranging from quirky crafts to waterproof basements. At other booths, local politicians will be the main attraction.

Still other vendors are in a category all their own. One woman had herself patented as the official tooth fairy princess and gives advice on dental care.

The fair will operate, rain or shine, from 7 to 10 tonight, from 10 a.m. to 9 p.m. tomorrow and Saturday, and from noon to 5 p.m. on Sunday. Admission is free.

Limited parking will be available at the center at 3501 S. Second St. Fairgoers are urged to take any of three shuttle buses that run every half-hour from the Court House Metro Station, from the Interstate 66 parking garage on North Quincy Street and from the Arlington Career Center parking lot, 816 South Walter Reed Dr. For more information, call 358-6400.