The bell-bottomed boys traditionally dominate this show, but the brightest star in this new revival isn't one of them: It's Megan Fairchild, a New York City Ballet principal now making her Broadway debut. That she's graceful and strikes breathtakingly beautiful lines was a given. Which is good because Fairchild plays a key role in this dance-heavy musical -- originally choreographed by Jerome Robbins, now by Joshua Bergasse. But it turns out the elfin ballerina's also a nimble, effortlessly funny comedienne. The show explodes with unfettered joy every time she's onstage. When she's not, it's more complicated...Betty Comden and Adolph Green's book and lyrics still crackle and pop after all these decades, and therein lies the rub: The show's already written funny, so director John Rando's frantic oversell can feel a little desperate.