Game show contestants sometimes grab national headlines by demonstrating a mind-boggling mastery of geography, history, science, and sports. Now, these celebrity contestants face off against mere mortals in “Best Ever Trivia Show,” hosted by Sherri Shepherd. It features a showdown between three ordinary trivia-loving contestants and three Trivia Experts. The Trivia Experts include Ken Jennings, Susannah Brooks, Ryan Chaffee, Muffy Marracco, and other heavyweights who have displayed an almost preternatural command of trivia during their storied appearances on “Jeopardy!,” “Who Wants to Be a Millionaire” and other game shows.