Acclaimed bad-boy playwright Tracy Letts ("Bug," "Killer Joe") is back and in top form with his latest dark comedy. "August: Osage County." In a sleepy Oklahoma town, three sisters rush home to their very unbalanced mother when their dad disappears. The gloves come off fast and the family heads straight into some very funny (and a little disturbing) territory in a show the Chicago Tribune calls "staggeringly ambitious — and, for my money, staggeringly successful."