Maybe it wasn't "The Night of 100 Stars," but call it "The Day of 50." Limousines lined a Broadway sidestreet, and a crush of fans snaked around the block--all to see and hear Ginger Rogers, Tony Bennett, Twiggy and a host of others pay tribute to the late Ira Gershwin.

Tony Bennett crooned, Jule Styne creaked, Cab Calloway cooked and Betty Comden and Adolph Green did their shtick. Fred Astaire, Gene Kelly and Irving Berlin sent telegrams. And composer Arthur Schwartz, a longtime friend and collaborator of Ira Gershwin's, revealed the long-lost original lyrics to "I Got Rhythm," which he said Ira penned as "dummy" words to get all the accents in place:

Roly poly--eating solely

Ravioli

Better watch your diet or bust.

Lunch or dinner

You're a sinner

Please get thinner

Losing all that fat is a must.

Words and music today were almost all by Ira and by George, and it happened on the stage of the erstwhile Uris Theater, recently re-named the Gershwin for the brothers. Ira Gershwin died Aug. 17 at age 86 in Beverly Hills after a long illness. But the mood of the occasion today, despite some tears, was as festive as a song he once wrote with Burton Lane. Lane belted it from the keyboard:

The state of the world is such

That the world is in quite a state

Let's not worry too much

Let the rest of the world debate.

Sitting in the audience of about 2,000 were some of the best and brightest of show biz as well as other notables: Garson Kanin and Ruth Gordon, Kitty Carlisle Hart, Joan Fontaine, Robert Merrill, Jack Weston, the Gershwins' biographer, Robert Kimball, and composers Morton Gould and Richard Adler.

"I love this, and the reason I love it is because it isn't sad," said Tony Bennett, looking tan, fit and perpetually curly. He sang the song that Fred Astaire made famous in the movie "Top Hat"--"They All Laughed (at Christopher Columbus)"--and also carried microphone stands around for the other performers. "You just know that these songs are gonna last," he said backstage.

Indeed, around the corner from the Gershwin at the St. James Theater, Twiggy and Tommy Tune are starring in "My One and Only," a new musical sporting old Gershwin songs. Radio City Music Hall just finished its revival of "Porgy and Bess," and New York is about to see the revival of the movie, "A Star Is Born," in which Judy Garland, playing opposite James Mason, sings music by Harold Arlen and words by Ira.

The limpid-eyed Twiggy and her beanstalk of a partner, Tune, came dressed all in white to sing "I like tomato, you like tomahtoh" and other favorite lyrics. Calloway, who played Sportin' Life in the 1952 production of "Porgy and Bess," pranced spryly around the stage to sing "It Ain't Necessarily So."

Comden and Green did "Of Thee I Sing," the title song of the musical that won Ira Gerswhin the Pulitzer Prize in drama in 1932. Ginger Rogers sang "Embraceable You," a song she said "I introduced in the first Broadway show I ever did, 'Girl Crazy.' "

Arthur Schwartz, reminiscing, described Ira as "a man with a wry sense of humor. I remember saying to him once, 'Just think of it. There have been 300 different artists who have recorded "I Got Rhythm." ' He just smiled and said, 'Yeah, some people seem to like it.' "

The cast locked arms at the end to sing "Our Love Is Here to Stay" with a slide of Ira Gershwin, smoking a cigar, looming behind them.

"If Ira knew about all this, I'm sure he would say, 'Why would people want to do a thing like this for me?' " said Marc George Gershwin, Ira's nephew and part of a family delegation that included Ira's widow, Leonore, his sister, Frances, and George's "best friend," Kay Swift. (George died of a brain tumor in 1937.)

Marc, the son of the third Gershwin brother, Arthur, and now a New York stockbroker, added, "Ira was a very humble man."

The regular folk started lining up outside the theater at 6 this morning for free tickets. "I really couldn't believe this was free," said Steve Stoliar, his tone grave with skepticism as he stood in line among other fans and autograph seekers.

The event was sponsored by ASCAP--the American Society of Composers, Authors and Publishers--of which Ira Gershwin was a longtime member. "To me," ASCAP President Hal David told the audience, "Ira was like a giant tree that you looked up to, a towering figure. As Americans, we are very proud of our institutions, and certainly the Gershwin name is one of America's great institutions."