Live from Lincoln Center, it was a crowd of 1,200 revelers in tuxedos and sequins, wedged shoulder to shoulder tonight on the Grand Promenade of Avery Fisher Hall to celebrate the 25th anniversary -- give or take a few months -- of the arts center's groundbreaking.

Downstairs, Lincoln Center chairman Martin E. Segal (rosebud in lapel) embraced New York City Ballet director Peter Martins (turquoise bracelet on arm) and greeted board member and labor leader Victor Gotbaum. "A nice bar mitzvah," said Gotbaum.

Upstairs, a svelte Beverly Sills accepted a glass of diet soda "with lots of lime. I've lost 55 pounds and I'm hungry," she confessed.

Few of the guests had such familiar faces: the $250-per-ticket gala was meant to honor "the people who made this possible," Segal explained. As such, several Rockefellers and Whitneys, executives of important corporate benefactors like Exxon and Texaco, members of various Lincoln Center boards and New York politicians far outnumbered artists. "A motley, interesting group," Segal called them. Placido Domingo, Zubin Mehta and Pinchas Zuckerman appeared only on film.

Walter Cronkite, one of several live guest narrators of a 45-minute filmed tribute to the center, chatted with historian Barbara Tuchman and told various inquirers that "the common consensus is correct: Mondale didn't score a knockout." His favorite Lincoln Center memory, Cronkite said, was the Metropolitan Opera's opening night, "with everybody being very bitter about losing the old hall and thrilled at the magnificent new one." Cronkite said he couldn't remember who sang, "but then, I can't remember baseball averages either."

Roone Arledge, shaking Cronkite's hand, said his most memorable time at Lincoln Center was "the first time I ever saw Baryshnikov dance. Afterwards, everyone came down and just stood by the stage and wouldn't leave. I never saw an audience do that." He particularly remembered the event, Arledge said, because "it was the day after Nixon resigned."

Avery Fisher looked pleased. When he signs charge slips in department stores, clerks are prone to looking up and asking, "Are you the hall?" He is, having underwritten its complete redesign (by Philip Johnson) and reconstruction with money from the sale of innumerable Fisher stereos. "It's a source of amusement," Fisher said. "Under normal circumstances, people with their names on concert halls are supposed to be dead. It's a lot more fun to be here." Alice Tully, who is also a Hall, was also toasting Lincoln Center's anniversary. She wasn't dead either.

Before heading across the plaza for dinner and dancing to the orchestra of Peter Duchin, the crowd watched the filmed montage of the arts complex's history and heard Philip Johnson confess, "When I designed the fountain plaza, I never dreamed it would become the site of the World Invitational Double Dutch Championship."

They applauded wildly for an exuberant group of students from the School of the American Ballet and sang "Happy Birthday" while a seven-foot cake was rolled onto the stage where the New York Philharmonic plays and they heard the irrepressible Mayor Ed Koch ("25 years ago I was a child") describe Lincoln Center as one of the city's three great cultural institutions. "I always include Lincoln Center and the Metropolitan Museum of Art." He said he never mentions the third -- it's a blank he can fill in depending on what institution he happens to be at. "I want to have it available wherever I go."