Just 12 actors will perform 57 roles in A.R. Gurney’s “The Dining Room,” in Riverside Military Academy’s Sandy Beaver Center Auditorium at 7:30 p.m. Oct. 18 and 1 p.m. Oct. 20. Admission is free. Riverside cadet cast members include Elijah Holyfield, Demarko Hooper, Stephen Wechsler, Robinson Whitaker and Sekayi Williams.