Hey, kids, let's put on a show! That's been the motif in innumerable showcases of young talent over the years, from Mickey and Judy musicals to Fame. The show the performers in Sarafina! put on is a matter of life and death. Mbongeni Ngema and Hugh Masekela's musical-within-a-musical recounts the slaughter of Soweto schoolchildren in 1976 and the systematic brutalization of young blacks under South Africa's "state of emergency" rules of the 1980s. But it's also a rousing, rafter-shaking celebration of the human spirit's capacity for endurance and even joy under the most awful circumstances. The show's pulsing score uses a style called mbaqanga, in which a throbbing, bass-heavy backbeat supports pungent, interlocking brass lines and brightedged, elation vocal harmonies. Its theatrical language is based on the group-oriented rituals of school activities which creates astonishingly complex levels of humor, horror, beauty, and irony when, for instance, a game of "all fall down" illustrates a soldier randomly spraying machine-gun bullets around a playground, or a choir directs a joyful Lord's Prayer to a seemingly inaccessible god. Visually the show is a study in rigid order-the high wire fence that separates the singers from the band members (who stand atop an army tank and sometimes wield their instruments like weapons), the prim black-and-white school uniforms the kids wear, the tightly arranged choreographic lines--until the end, when the performers doff their jackets and ties for dazzlingly colorful dresses and loincloths for an explosive display of athletic tribal dance. Among the superbly taut ensemble--mostly South Africans singing in English and Zulu--keep a close eye on Baby Cele as the sassy schoolteacher with the piercing whoop, the incredibly expressive singer Thandi Zulu, and Leleti Khumalo as Sarafina, the girl whose indomitability even after prison torture inspires the other students. At the New Regal Theater, through April 21. Tuesdays and Thursdays-Saturdays, 8 PM; Wednesdays, 10:30 AM and 8 PM; Sundays, 3 and 7:30 PM. $15-$35.