The Washington National Opera company kicks off its new season with Opera Colorado's production of Giuseppe Verdi's Un Ballo in Maschera, about a king who foolishly falls in love with his best friend's wife. Not even a king should do that, as related in this grand opera about forbidden love and revenge and featuring soaring arias, gorgeous ensembles, fabulous costumes and lavish sets. Tenors Salvatore Licitra and Frank Porretta share the role of King Gustavus III, joined by sopranos Tamara Wilson and Irene Theorin as the innocent wife Amelia, and Luca Salsi and Timothy Mix as the aggrieved husband and best friend Count Anckarström. Mezzo-soprano Elena Manistina sings the pivotal role of the fortune teller. Opens tonight, Saturday, Sept. 11, at 7 p.m. Performances through Sept. 25. Kennedy Center Opera House. Tickets are $55 to $600. Call 202-467-4600 or visit dc-opera.org.