"No, No, Nanette" is one of those Broadway musicals that is the perfect combination of tap and tune _ catchy songs and dance numbers guaranteed to get an audience giddy.

It did in 1925, then again in 1971 and now, 37 years later, that fizzy feeling is back, courtesy of City Center's "Encores! Great American Musicals in Concert."

If any show epitomizes the exuberant, frivolous gaiety of 1920s musical theater, it is this concoction, which features a hypnotic, hummable score _ music by Vincent Youmans and lyrics by Irving Caesar and Otto Harbach.

The production, which runs through Monday, has had a convoluted parentage. It is an adaptation of an adaptation. The book for the original "No, No, Nanette" (by Harbach and Frank Mandel) was reworked for the '70s revival by Burt Shevelove. That show, streamlined even more by David Ives, is what has found its way to City Center.

Casting is crucial for "Nanette," the intertwined tales of a young woman's modest rebellion against propriety as well as the extramarital (yet totally chaste) shenanigans of her uncle, a wealthy Bible salesman.

In 1971, the key element was Ruby Keeler, Hollywood's favorite shy, sweet-tempered hoofer, returning to Broadway for the first time in more than 40 years. Now, we have Sandy Duncan (in Keeler's role as the Bible salesman's understanding wife) back on the boards, also after too long an absence.

Duncan always shone best on stage and it's a shame Broadway hasn't seen more of her over the years. She exudes a cheerfulness and can-do-personality that's shown off to best advantage by a proscenium arch. Television and movies never did her justice.

There's also a charming physicality to her performing, a trait that "Nanette" perfectly uses in its big dance numbers, two of which put Duncan front and center. Randy Skinner's choreography, primarily of the tap variety, mirrors the fun of the show's music, particularly its two best-known songs, "I Want to Be Happy" and "Tea for Two."

The first encapsulates the show's sunny personality, a generosity of spirit (laced with a sly wink) found in the lyric: "I want to be happy but I won't be happy till I make you happy, too." Watching Duncan and company enthusiastically work their way through this number can't help but make spirits soar. Continued...