A joyful celebration of art and life filled the Kennedy Center Opera House last night with a playwright's knowing wit, the melancholy twang of electric guitars, the dancing of children, an actor's powerful grace and a diva's soaring splendor.

An adoring audience of lawmakers, music legends, actors, socialites and even a few regular folks gave a series of warm, lingering standing ovations for the five American artists honored at the 18th annual Kennedy Center Honors gala -- dancer Jacques d'Amboise, mezzo-soprano Marilyn Horne, bluesman B.B. King, actor Sidney Po\itier and playwright Neil Simon.

The performances lauded the honorees for their lifetime of devotion to the arts and, as master of ceremonies Walter Cronkite put it, saluted "artists who have made the most splendid contributions to our national soul." The entire evening underscored the way in which song, dance and poetry can transcend human differences, enlighten and uplift. (Heck, even President Clinton and House Speaker Newt Gingrich shook hands from their respective boxes.)

It was a night that culminated a long weekend of dinners, receptions and adoration by, among others, the president and Mrs. Clinton, who received the honorees at the White House.

But the gala, to air on CBS Dec. 27, was where friends came to honor friends. Said Steve Martin, who was there to pay tribute to Simon: "We're here to honor him tonight for scale." He also praised Simon strongly for limning the "simple joys and pains" of life.

Actors Christine Baranski, Sid Caesar and Nathan Lane reminded the audience of Simon's prolific wit with excerpts from his plays.

Charlotte and Christopher d'Amboise danced for their father, and so did 100 children from the National Dance Institute, which Jacques d'Amboise founded.

Blues greats from Etta James and Bonnie Raitt to Dr. John and Joe Williams paid their musical respects to King.

Singer Frederica von Stade said of her friend, Marilyn Horne, "Her voice is married to an all-powerful spirit that fills a stage and redefines the greatest roles of opera. She is song."

As for Poitier, his old pal Paul Newman took the stage to kid him a bit and then to praise his "pilgrimage of startling grace. . . . He has changed the face of film itself." As the audience stood and roared its approval, Poitier, the first black actor to carry a movie, stood next to the Clintons, who were also applauding, and soaked it all in. He then threw his arms wide to give it all back. The audience just kept on applauding.

After midnight at the post-gala banquet, a jazz band played and dolled-up guests at the 145 tables dined on chicken pot pies (no kidding), blanched vegetables and apple-cranberry cobbler.

Trumpeter Wynton Marsalis looked longingly at the working musicians. A few brave souls hit the dance floor, and, later, people began gathering on the nearby steps awaiting what promised to be -- if tradition held -- a late-night jam session.

Sure enough, by 12:30 a.m., Joe Williams had the mike in his hand and was crooning "Tenderly." "He's wonderful," said Kennedy Center volunteer Trina Leonard. "He sings almost every year.

"I really look forward to it." Presidential Decree

It was, said President Clinton, "the summit of five lives of artistic grace."

At the White House reception, just before the gala, six Christmas trees towered above four rows of golden chairs in the East Room. In the crush most guests stood, and even Sarah Ferguson, the Duchess of York, only managed to snag a fourth-row seat. In every direction there was a famous face: Steve Martin, Martha Stewart, Jessye Norman and more.

Mrs. Clinton wore a red ball gown. The president wore a touch of jet lag. The two, having just returned from Europe, had only a couple of hours before they had to put on their formal finery.

"All of us know our nation and our world are in a period of profound change. We have to do everything we can to imagine the right kind of future," said Clinton. "At this time we need our artists in a special way, in a profound way."

Each honoree then received an official handshake -- except Horne, who sang at the Clinton inauguration. She received a presidential kiss on the cheek. Naked Brunch

Grinning, Jacques d'Amboise was telling a table of friends a little story about Neil Simon during yesterday's spiffy brunch at the Ritz-Carlton for the honorees and their families, plus assorted movie stars, producers, show biz friends, political types and other all-American honchos.

"Neil," he said, "was suggesting after we got our medals Saturday night that we should all, at midnight, stand in front of the mirrors in our hotel rooms naked, wearing them."

And, d'Amboise added, "I did it. I really did it. It was fun."

"I did it, too," Simon said.

"But he wore his pajamas," the dancer said.

"If I had his body," the playwright said, "I'd have done it naked, too."

Nearby, actress Cicely Tyson, a member of the Kennedy Center committee that chooses the honorees, was taking her opportunity to meet B.B. King for the first time, except for a brief encounter once at the Emmy Awards.

"I just want to tell you, I've enjoyed your work so much over the years," she said. They chatted, and then he gave her a little pin representing his famous guitar, Lucille.

"I love the depth of this man's soul," Tyson confided later.

"I'm still kind of dreamin' and startin' to wake up into reality," King also confided later. "I still can't believe that it's me. I hope they didn't make a mistake."

One table over, Sidney Poitier -- imposingly tall, square-shouldered and gentle of manner -- was sitting with family and friends, including five of his six daughters.

"It's going to take a bit of getting used to, for me," Poitier said of his award. "Certainly when I started in the theater, I . . ."

"Dad," a daughter interrupted.

Poitier excused himself to help one of his friends, who was in frail health, get properly positioned at the table. Then he continued: "I had dreams, of course, though one didn't flirt with expectations too openly. But my dreams did not include receiving that medal last night. Last night was in an area far beyond my dreams."

His daughter Sherri, 28, looked admiringly at her father and said, "It's just a wonderful feeling to be so proud of your parents, to be the eyes for my grandparents -- to see what their son has accomplished."

"He's a miracle," said George Stevens Jr., the producer of the gala and host of the brunch -- a view of Poitier that seemed to be shared by everyone.

Stevens added that he's been going around saying that "this is a time in Washington of cutbacks, and so we'll do a very dull and quiet show this year, to not seem expensive."

Joke!

Meanwhile, out by the buffet tables laden with miniature Jockey Club crab cakes meuniere, petit rack of lamb, chilled fresh asparagus vinaigrette, baked eggs Florentine, smoked Norwegian salmon and so on, Secretary of Health and Human Services Donna Shalala was loading up her plate and allowing as how it was a few notches up from your average Washington political feed. "It's civilized," she said. "It's because the Stevenses are putting it on, and they're civilized."

Politicians such as Reps. John Lewis (D-Ga.) and John Dingell (D-Mich.) and Sen. William Cohen (R-Maine) were drifting here and there -- no match for the stars, really. Marilyn Horne apparently didn't attend, though someone said she might have slipped down from her room early just to nip at some of the gorgeous food.

James Earl Jones, the great baritone voice-over among other things, said he was "overwhelmed" at the State Department Saturday night to see "everyone from General {Colin} Powell to Jane Alexander. They're all legends to us."

"And I didn't say the f-word!" added his wife, Cecilia, enthusiastically. Enter Glamour

The white masking tape on the burgundy strip of carpeting looks forlorn. It marks the spot where the Kennedy Center honorees, their guests and assorted celebrities will be asked to stop, pose and smile for the cameras. It is the place where glamour and excitement will be captured in a flash.

But at this moment, on Saturday night, there is no glamour. There is only the near-empty foyer of the State Department, a row of metal detectors and a host of security guards waiting for something to secure.

The first of the celebrities to arrive for the black-tie dinner at which the honorees will receive their rainbow-colored award ribbons is Lou Gossett Jr. and his guest, Elize Gazzar. He is in a black jacket with a standing collar and black suede Gucci loafers. She is in a floor-length gray lace gown. They are pleasant; Gossett is famous; but they don't do glamour. Then opera diva Leontyne Price makes her grand entrance. Spying Tyson -- in a tomato-red turban -- she smiles and cries, "Ciao, bella!" And kisses are blown to the wind.

Glamour has arrived.

Later, up on the eighth floor, famous cheek brushed equally famous cheek in an ornate room filled with portraits of long-gone Americans, a slow-moving receiving line and waiters delivering champagne to the swanky crowd. The honorees each staked out a bit of real estate and with slightly dazed expressions accepted congratulations.

"You go through degrees of excitement," said Neil Simon, who arrived with his wife, Diane, and his daughters Bryn, Ellen and Nancy. "The most exciting is when you get the letter telling you you're an honoree, and they ask if you'll accept.

"Like you're going to say no."

Nervousness strikes only when he's watching one of his plays.

"He's terribly vulnerable," said Christine Baranski, a theater veteran and now best friend Maryann on TV's "Cybill." "He almost has a slightly anguished look on his face, wondering if it's going to work."

Said friend and screenwriting legend Larry Gelbart, "If he doesn't choose to rest on his laurels, I can only assume he's afraid of heights."

Tickets for the Kennedy Center Honors sell for as much as $2,000 each. And buying one doesn't guarantee an invitation to the State Department dinner. This is a highfalutin, who-do-you-know affair in a room with eight chandeliers and flickering candelabra on every table. Place cards are embossed with gold seals, and everyone has a formal title. This year's ranged from Gen., as in Colin Powell, to Mrs., as in Barbara Davis. She, by the way, created one of the many fashion buzzes of the evening in a Vera Wang ball gown complete with rose satin skirt and a bodice that was part sheer black netting.

Michele Lee was all cleavage in an ivory satin double-breasted suit with pleated trousers. And she couldn't stop hugging Poitier and proclaiming, "I'm so happy for you."

Poitier, by the way, should receive a special award for having the most attractive entourage. As he stood receiving congratulations, he was surrounded by his wife and five daughters -- all statuesque, elegant and with hair that was braided, curled, twisted or tousled.

"One's life arcs," Poitier observed, getting extemporaneously philosophical. "For one to come to this place . . . one must have some life and values that have accumulated."

Then Gossett arrived to offer a bear hug. Po\itier, who grew up in the Bahamas, is a distant cousin, Gossett said -- if you have roots in the Bahamas, "everyone is everyone's cousin." But Po\itier, he added, also is "my idol."

Horne held court from a gold velvet chair. In her left hand she clutched a multicolored cloisonne cane purchased from the Smithsonian museums catalogue. Five weeks ago she had double knee replacement surgery, and a simple wooden cane would have detracted from her copper and silver tuxedo jacket and black velvet palazzo pants. The diva wanted enamel.

She looked around for King, the only honoree she hadn't met. For his part, King was just pleased to be receiving the award now rather than posthumously.

"I was here before, as a guest," he said. "I thought then, silently to myself, that I'll never live long enough to receive such an honor. Why would anyone think of me, a guy from Mississippi?"

Now, though, people such as James Earl Jones, Powell and Jack Jones ("I once had the audacity to sing the blues with you and Aretha") are waiting in line just to say hello. "60 Minutes" reporter Ed Bradley proudly reminisced about the time he played tambourine with King.

D'Amboise was feeling numb. He had been listening to King's music just before dinner, and now he was about to meet the blues legend. But he was beating any nervousness by imagining the many celebrities and dignitaries as small children. Sid Caesar in a sandbox. Walter Cronkite on a swing. Tyson with a Barbie doll.

Musician Herbie Hancock, on the honors nominating committee, was hoping to see some politicians up close: "To see what they look like and to see if they're honest."

When the awards were all handed out and the group picture snapped, everyone retreated to their limousines and waiting cars. The music stopped. The champagne was finished. And the State Department was once again filled with just black and white marble and a forlorn strip of red carpeting marked with a big white X.

Glamour had gone home. CAPTION: Jacques d'Amboise and wife Diane, above, and Marilyn Horne at Saturday's dinner at the State Department. CAPTION: From left, Neil Simon and Sidney Poitier at yesterday's brunch; B.B. King arrives at the Kennedy Center; President Clinton with Marilyn Horne and Jacques d'Amboise last night. CAPTION: Sarah Ferguson, the Duchess of York, was among the famous faces at last night's glittery gala. CAPTION: Lynn Redgrave and Joe Williams chat over brunch at the Ritz-Carlton. Below, honorees Jacques d'Amboise, left, and Sidney Poitier at the Kennedy Center.