On a wintry Saturday in Cambridge, MA, I joined friends and family at the American Repertory Theater to watch Eve Ensler’s new comedy, “O.P.C.” Eve Ensler, writer of the well-known “Vagina Monologues,” is no stranger to provocative topics, and “O.P.C.” well suits her brand. The play explores overconsumption: The fact that Americans throw away $165 billion worth … More “O.P.C.” touches on millennials’ big questions