The Oklahoma History Center is pleased to announce a performance in the Kilgen Organ series featuring organist Brett Valliant. The theme will be “Discovering the Unit Orchestra.” This performance will be Monday, October 26, from 7 to 8:30 p.m. Tickets are $10 for Oklahoma Historical Society members and $20 for nonmembers, and may be reserved by calling 405-522-0765. Doors will open at 6 p.m. and seating is on a first-come, first-served basis.