STAGE

Starting at the top and working down: Rory Calhoun and Sidney Poitier will tap into some show-biz basics when they appear at tonight’s opening night of the Buckley School’s presentation of “Grease.” Calhoun will sing. Poitier will dance. Both have been cast in the chorus line. Role reversals? Career comedowns? Not quite. Calhoun and Poitier are both namesakes and teen-aged daughters of veteran Western star Rory Calhoun and Oscar-winning actor-director Sidney Poitier.