Who would have suspected? While school boards in Arlington, Fairfax and Montgomery busied themselves with controversial school closing decisions last week, the Prince George's Board of Education was busy making whoopee.

It wasn't planned. Item eight on the agenda seemed innocent enough: "Presentation -- Duval High School Band." Board member A. James Golato was proud of the band (it's listed in the Guinness Book of World Records for a 100-hour, two-minute rehearsal in 1977) and asked its members to play at last week's meeting.

But as board member Jo Ann Bell pointed out, Cole Porter's "Begin the Beguine" was "an old, old favorite."

"Oooooh," she sighed when the opening bars were played. She rose to her feet, marched around the board table past the administrators and assistant superintendents, and before Deputy Superintendent Allan I. Chotiner could rise on a point of order, he was whirled across the room, kicking his heels over microphone wires.

Board chairman Doris A. Eugene was quick to follow, dancing with her deputy, Angelo Castelli, in the corner of the room by the coat racks. Board members Catherine M. Burch and Golato danced behind the chairman's chair.

Who would have thought that a school board, with next month's battle for a budget the county executive says it can't afford hanging over its head, would behave this way?

Perhaps its members were trying to build confidence. Much of the meeting was devoted to self-congratulation. New board chairman Eugene presented her predecessor Bell with an inscribed plaque. Bell returned to her desk and pulled out a plaque to give to Eugene.

School Superintendent Edward J. Feeney presented the board with a 17-page list of the school system's accomplishments over the past five years. He also introduced board members to Sheila Johns, board member Bonnie Johns' actress daughter, home for the holidays. "A dear friend," Feeney said.

Then Golato, wearing the hat of administrative committee chairman, spoke glowingly of a Washington Post editorial last week that criticized Montgomery's school board and praised Prince George's Eleanor Roosevelt High School.

The Montgomery school board used to be lauded as a model of excellence, Golato said later. "And Prince George's was way down there," he added, lowering his left hand to the vicinity of his left knee. "Now it's the other way around."

Even the board's attorney, gruff Paul Nussbaum, who will be sharpening his arrows this Christmas for the NAACP suit against the school board that begins next February, seemed cheerful.

He came to the meeting in his usual conservative gray suit, but was sporting a bright pink shirt, a new haircut and a big smile. He was not consulted on anything last Thursday night and volunteered nothing. He didn't even open his briefcase.

There was serious business to be done, of course, but not until the "Woodchoppers' Ball" and the "Boogie Woogie Bugle Boy" had been played. "And now we will go back to the agenda," Eugene said, turning to Feeney. "Do you have your report?"

"It isn't fitting for school board members," Golato said as he recovered from his dance. "She asked me. I was embarrassed." Which was an odd thing to say, for Golato spent six months of his youth as a professional dancer, jitter-bugging his way across music hall stages in the Philadelphia suburb of Conshohocken.

Deputy Superintendent Chotiner, who has been with the school system 31 years, was bright red when he finished dancing. "I don't know why she picked me," he complained. "I guess it's because I'm old-fashioned. I get embarrassed. I'm very shy."

Bell said she first danced with Chotiner at a conference of superintendents and administrators four years ago. Since then, she said, the deputy superintendent has panicked each time he sees Bell and hears music at the same time. Once when he saw her stand up, she said, "He scooted out of the room." But beneath his bashful exterior, she said, "He's really just a jitter-bug, waiting to get out."