What happens when an opera company imports a world-famous tenor to launch its season, only to find that said tenor has passed out cold from taking too many tranquilizers? The show must go on — even if it means replacing the star with the director's assistant. Eight O'Clock Theatre opens a limited run of Ken Ludwig's Tony-winning backstage farce, Lend Me a Tenor, this week. 8 p.m. Thurs.-Sat., 2 p.m. Sun., May 2-11, Largo Cultural Center, 105 Central Park Drive, Largo, $21 general/$16 students, 727-587-6793.