I caught "Frost/Nixon" on stage last week at the Ahmanson. Stacy Keach as Nixon was the show's most powerful performer and crowd pleaser. Alas, he's out indefinitely after suffering a mild stroke yesterday. Understudy Bob Ari went on last night and will stay in for the meantime. "Ari also understudied the part on Broadway, with Frank Langella as the former president in Peter Morgan's drama about Nixon's duel of wits with David Frost during a series of 1977 interviews," says Culture Monster. Ticket refunds or exchanges are available, the Ahmanson says.