Taylor Caldwell Photo by Joan Marcus

It's not so much that the show dates to 1975, or even that it is based on a collection of books written by Sendak in the early 1960s. It's that, in its structure, Really Rosie is a throwback to those long-ago days when summertime for kids meant sending them outside to play and leaving them to their own devices to figure out, as the title character sings, how to "turn twelve boring hours into a fascinating day."

Instead of playing stickball or red light/green light, the kids in Really Rosie play games of make-believe, under the watchful and demanding eye of the ever-melodramatic Rosie (Taylor Caldwell). She leads them through a day of imagining they are about to be visited by a Hollywood producer who wants to make a film about our heroine and the "tragic death" of her annoying little brother, Chicken Soup (Zell Steele Morrow).

The show itself, which began life as an animated thirty-minute made-for-TV special and was later expanded to 70 minutes for the theater, is little more than a series of unconnected musical numbers. The characters are drawn from Sendak's "Nutshell Library" books (plus an additional one just about Rosie): Chicken Soup, Alligator, Johnny, Pierre, and the rest of the kids from Brooklyn's Avenue P. Carole King has provided a bouncy score, nicely backed by a five-piece band, with pianist Carmel Dean serving as conductor. And, if you listen carefully, you will occasionally hear echoes of some of King's more popular earlier tunes ("I Feel the Earth Move" and "It's Too Late").

The premise that explains the movement from one number to the next is that the kids are auditioning for the movie. As Rosie tells them, "I'm sending you out a boring stupid kid, and I want you to come back a fantastic bit player star!" That's basically the show, a series of songs with modest choreography (mostly tap) by Ayodele Casel. The cast of youngsters includes several with Broadway experience, including Anthony Rosenthal (Falsettos), Zell Steele Morrow (Fun Home), Taylor Caldwell (School of Rock), and Eduardo Hernandez (On Your Feet). Grown-up Charlie Pollock lends the show its only funny bits aimed at adults as he comically voices several of the kids' mothers and appears as a lion in one of the songs. Overall, however, director Leigh Silverman hasn't found much to spark the show into life, and the overall effect is that of a nice little children's theater production that has somehow found its way into the vast venue of City Center. Of that, at least, Rosie would be most proud.

Really Rosie
Through August 5
New York City Center's Mainstage, 55th Street between 6th and 7th Avenues
Tickets and current performance schedule: nycitycenter.org