Fox has ordered two more seasons of "The Simpsons," making the animated show the longest-running series in prime-time TV history. The 44-episode two-season pickup brings the show's total to 493
episodes. Previously, CBS' "Gunsmoke" held the record as the longest-running series, on the air for 20 years, from 1955 to 1975, with 635 episodes). "The Simpsons" debuted in 1990.