"I've wanted to do it all my life. But I came from an area of the country where it was a sin to do it. Now, at 55, I'm doing it."

No, sorry, Carole M. O'Connor is not talking about that. In fact, talking itself appears to be a bit of a burden, for she is somewhat out of breath. But an innocent has just asked what a nice girl like her is doing in a place like a tap dance studio. Expecting a mere fan, the innocent has uncovered a zealot.

"I'm in the groove," O'Connor says. "I don't want to quit now. This is the culmination of something I've always been dying to do." And with that, she is off in search of the sign-up list for the March soft-shoe classes.

So it goes on Sunday afternoons, in a walk-up dance studio at Connecticut Avenue and Newark Street NW. About five dozen Washingtonians of every size, shape, sex and skill show up for lessons in clowning, juggling, tap dancing and jazz dancing offered by the Open University of Washington.

They are not budding Fred Astaires or Emmett Kellys, although some confess to harboring a fantasy or three. And they are not always there strictly for art's sake ("This has become Washington's new singles bar," declared Dan Smith, a Sunday clown).

Nor are they the have-makeupwill-travel diehards of "a Chorous Line." Dancers show up in everything from tutus to togas, and one tapper refused to part with his dress shirt, his tie and his oxfords.

But to say a good time is had by all is the same as saying rivers run downhill.Even the most confirmed crab would find the weekend hoofing obviously cheering. There is so much spirit that one wonders whether "Star Wars," playing across the street, might not do well to make way.

All the more so every fourth week, when the jugglers, clowns and dancers give an informal "graduation performance" -- the capstone to a $30 package of four lessons. It was graduation day last Sunday, and there at the wheel as usual were the man-and-fiancee team of Joe Jeff and Nancy Lynner.

Jeff is the dancemaster, Lynner the mime, juggling and clowning specialist. As teachers, they both get results. But in terms of technique, they could not be more of an unmatched set.

Where Jeff is boisterous, bouncy and creatively insulting ("You still looked like an emphysema ward that time," he told his jazz dancers), Lynner is calm, patient and soothing. But both say their reward is identical.

"After six hours, these apparently sedentary people really learn to tap dance," said Jeff. "It's great to see how much people can learn," added Lynner.

The people agree. "It's a heck of a lot tougher than I thought it would be," said Harold Winer, who at 68 was outstrutting some folks half his age. "Tap dancing looks so graceful and so easy, but I've learned that it isn't. Now I only wish my grandchildren could see me."

Charles Kubinski, an attorney, acknowledged that, even after four lessons, "I can't dance worth a damn." But he said tap class has led to many a diverting, exerting evening of practice in the family basement.

Besides, said his wife, Carryn, "You come in here with a hangover and it's over by the time the class is."

More striking than any alcohol poisoning are the changes normal people undergo as soon as they get within hailing distance of the greasepaint.

Fred Emery especially. All week, he is a government attorney. All Sunday, he becomes Duffer, a golf clown.

Last Sunday, Emery was a smash in his bright green wig, his beach-bum surfing pants and a nose that had the shell of a golf ball pasted over it.

"I just love this," he said. "Love the whole 27,000 things you're supposed to keep in your head."

One of his clowning cohorts, Joey Stephens, a 19-year-old coding clerk for the Navy Department, said she plans to make practical use of the class. "To entertain my nephews," she said.

Bobbi Pollack, another clown when she isn't an American University law student, said she has professional dreams. "I'd like to do children's parties and that kind of thing," she said.

She might have wandered across the hall, where Joe Jeff's tap class was in high gear. The giggling that wafted through the door had the same ring as it does during pin-the-tail-on-the-donkey at an eighth birthday.

"Don't enjoy it so much!" Jeff was shouting, tongue firmly in cheek. "I want you to knock Mr. Merrick out of his seat when you audition for him."

Even though he did not look the part, dressed as he was in a tee-shirt that read "Wonder Man," Jeff led his class a little later through a bit of minister-instructs-congregation.

"To dance is as natural as to . . ."

"Breathe!" huffed his class.

"And when I ask you to do something, you don't say 'OK' or 'Yes'. You say . . ."

"We'll try," replied the class. After all, show biz makes you humble, sooner or later.

Late Sunday, Jeff and Lynner had five minutes between classes. They stole a kiss, and an apple apiece. Midway down to his core, the mental light bulb lit in Jeff's eyes. He had just thought of what the Sunday Strut really means.

"I had a psychiatrist taking the tap class once," he said, "and he refused to stop after the four lessons were over. 'It's my therapy,' he told me, 'and nobody takes my therapy away from me.'"

One could almost hear Gene Kelly singing. "They Can't Take That Away From Me." And dancing, of course.