Most people would observe their 75th birthdays either with paeans to their triumphs or, in cautious cases, with silence. Saturday night, producer Roger L. Stevens did neither. He charged $750 a seat for his 75th-birthday gala at the Kennedy Center and devoted it to the high points of the shows that were his theatrical low points.

The celebration of the glories of failure turned out to be one of the freshest, most alluring presentations Stevens has produced. For more than an hour, beguiling material overflowed from 10 of his shows that didn't make it, sounding as fine as most of his shows that did.

It was, as they say, a "fitting tribute" to the man who, as Sen. Edward M. Kennedy (D-Mass.) told the crowd, could "give a quiet nod and 'West Side Story' appears."

This willingness to take risks and, observed violinist Isaac Stern in his toast at the postperformance dinner for nearly 400 invited guests, "to help others to be able to do things that he himself would have loved to do" has been a recurrent theme in Stevens' career -- whether on Broadway or in creating the Kennedy Center.

Guests came from all segments of Washington -- social, political and artistic -- and the money raised goes to benefit the Kennedy Center. They included Mayor Marion Barry, National Gallery Director J. Carter Brown, Washington cave dweller Evangeline Bruce, Washington Performing Arts Society Director Emeritus Patrick Hayes, former senator Charles Percy, Wolf Trap founder Catherine Shouse, Motion Picture Association of America chief Jack Valenti and Defense Secretary Caspar Weinberger. Following the concert in the Terrace Theater, they dined on smoked salmon, leg of lamb and fruit sherbets in the Kennedy Center's Theater Lab.

One of the most eminent guests, composer Leonard Bernstein, was recalling recently that the "quiet nod" for "West Side Story" that the senator referred to actually came in response to a panicky transatlantic phone call. One day in the mid-'50s, Bernstein, director Jerome Robbins, author Arthur Laurents and lyricist Stephen Sondheim (well into the work's composition) found themselves standing on a Manhattan street corner, having just been told by the initial producer that the show was too risky, and that they could forget it.

"We were desperate. And we remembered that Roger had expressed an interest in buying into it. We went to a phone booth there on the corner and started trying to find Roger. His office finally tracked him down in London. His answer was simple: 'Keep writing.' " Among other things, Stevens recalled recently, he made more money from "West Side Story" than any other of the roughly 200 shows in which he has had an interest.

Saturday night, Bernstein told Stevens, "Thank you so much for 'West Side Story' and especially for 'Mass,' " the Bernstein work commissioned for the Kennedy Center's opening.

Kennedy recalled that Stevens' sagacity extends to politics as well, referring to the failure of the bicentennial musical, "1600 Pennsylvania Avenue," which provided the climactic material for this concert.

After Kennedy's 1980 bid for the Democratic presidential nomination failed, he said, "Roger told me, 'I want you to know that I once made a play for 1600 Pennsylvania Avenue as well, and I closed too.' But as Roger told me, 'There's always another show' " -- a prospect greeted by cheers from the audience, or at least some of it.

Tracing Stevens' career as founder of the National Endowment for the Arts, as well as prime force in creation of a national cultural center, Kennedy wryly referred to Stevens as "the Robin Hood of the performing arts," who had made a career of "robbing his friends to help the arts." And in a moving moment, the senator recalled his brother's fondness for Stevens, adding, "I know that if Jack were with us today he would honor Roger for having realized his vision for the arts."

Earlier in the evening, Stevens, who is also observing his 25th anniversary as chairman of the cultural center and whose birthday was actually last March, described his relation with the former president in a television interview:

"He was so supportive. And I felt that we had to get it finished for his sake. I remember several times I said to him, 'Mr. President, I'm doing a bad job. You better get somebody else.' And, in that inimitable way of his, he would say, 'Roger, this is the hardest money-raising job in the country. And I know it. I'll help you.' And he sure did."

It was Stevens who, after Kennedy's assassination, proposed making the cultural center the nation's memorial to the president. He raised the money for its construction.

Saturday night's concert was in two parts. Following a welcome by philanthropist David Lloyd Kreeger and Kennedy's speech, the first part consisted of an all-star classical recital. There was the two-movement Mozart Sonata in E-minor, K. 304, one in which the material for violin and for piano is fairly evenly matched. Stern showed his usual fluency in Mozart. And the piano playing of Leonard Bernstein served as a reminder of how the time demands of his genius as conductor and composer have robbed the world of a pianist of the first rank. Aside from one minimally flubbed note, Bernstein was perfection -- phrasing, dynamics and the rest in remarkable focus.

Then National Symphony Orchestra music director and cellist Mstislav Rostropovich played three short and dazzling works of Bach, Weber and Shostakovich (with pianist Lambert Orkis). His command of pitch and dynamics never seemed more awesomely assured (those glissandos in the last work were really something). Then Rostropovich dashed off to conduct the NSO in the Concert Hall, returning to deliver his toast at the dinner.

Then came the revue of would-be hits from the flops, or as emcee Kitty Carlisle Hart put it, "works which closed prematurely." Some had respectable runs, like "Peter Pan" (1950) and "The Golden Apple" (1954) and "Lost in the Stars" (1972 revival), but didn't make money. One, "Colette" (1982), started in Seattle and never got east of Denver, despite the lovely "The Room Is Filled With You," beautifully sung by Martin Vidnovic.

Romance was an almost consistent theme (could that have been the problem?). All the performances were splendid. And several clearly wowed the audience: the sinuous dancing and lovely singing of Jane Summerhays in excerpts from the revived "Oh, Kay!" of the Gershwins; the real pathos of Elaine Stritch in excerpts from "Goldilocks" (1958).

All made you want to hear more, regardless of the original fates of the shows.

The most tantalizing of all were the four excerpts from "1600 Pennsylvania Avenue." Is there a more distinctive solo scene in the American musical theater than Patricia Routledge's "Duet for One"? And who would dispute that "Take Care of This House" is one of the greatest Bernstein ballads? Yet the show both opened and closed in this city. And those who saw it will remember why: the finest numbers cannot save a show that does not make sense as a whole.

At the end, Hart dragged the nonetheless proud (and justifiably so) producer onto the stage. A speech was expected. But Stevens' only response was, "The best I can say is that I am overwhelmed." For those up close the reason was clear. His eyes brimmed uncharacteristically with tears.