IT'S ONLY 12:30 and the movie doesn't begin till 1, but already the regulars are drifting into Circle Theater.

There's Mr. Sleepy, who pays his dollar and takes his lunch box and flashlight down to his customary seat, fourth row left. He will sit through all three showings of the double feature and will be awakened by the night manager when the place closes.

There's Mr. Smoky, who keeps forgetting himself and lighting up in the dark. He complies politely when told not to smoke. But he does keep forgetting.

There's Mr. Changer, who stands jiggling on one foot in the lobby endlessly fishing for coins. And the bag lady who takes her bath in the washroom. And the people who yell at the screen and quietly have to be encouraged to take it easy, it's just a movie. And the waiters in uniform who drop by to fill a couple of hours between lunch and dinner. And the GW University students playing hooky. And, of course, the buffs.

The Circle, Washington's premier repertory movie theater, is an institution. You have a yen to revisit an old Ingmar Bergman picture you loved? It's bound to come back to the Circle yet again one of these days. You never saw the classics, "Rules of the Game" or "Grand Illusion?" The Circle runs them every year or so--as a double bill. You missed one of those new movies that was supposed to be so great but was shelved after two weeks? Hang in there, the Circle will have it. But you have to move fast, because pictures only stay a few days.

During the peace marches of the '60s, the Circle, like some other downtown theaters, stayed open all night for kids who needed a place to sleep, free.

"We try to make people comfortable," says day manager Hossein Ghahari, who, as the projectionist, knows a vast number of films by heart. "Some people have no place to go."

Coming off the noon-bright street, you pay your dollar to Juliet, the cashier, stroll past the stacks of battered film cans and get your ticket torn by a very short, very old, very formally dressed man.

This is Dad, the father of Ted and Jim Pedas, who founded their local theater empire with the Circle in 1957. Dad is 90, and he has been a fixture in the lobby for 18 years. He has not been around much recently. Last year he suffered a small stroke, and when his son put him in the car he asked, "Are we going to the theater?" "No, to the hospital," Ted said.

Ghahari has been with the theater 18 years, too. He comes in on his day off sometimes. The Pedas family is his family, he says.

Walking down the steep aisle, you find your spot. By some mysterious agreement the back curtain of the candy counter is lifted, throwing light down the center so early birds can read. The dreamy, smoky Stan Getz record of "The Girl From Ipanema" is playing. It is almost always playing. The minute the movie stops, there is Stan Getz again. Sometimes it keeps playing after the next movie has started, and people storm the box office.

On the screen, in "Funny Face," Fred Astaire is about to discover that the little bookstore clerk is not only beautiful but is Audrey Hepburn.

The Circle may be torn down eventually for a new office building, but the Pedas brothers vow they will replace it. No doubt they will keep the carpeting, a sort of Kandinsky squiggle that is a trademark of Pedas theaters. Maybe they'll even bring along Stan Getz.

Now Audrey Hepburn has been inveigled into being a fashion model, batting her famous eyes. She is in the co-feature, too, "Breakfast at Tiffany's." I had forgotten how much she looked like Bambi.