What’s coming up on ”The Simpsons.” Guest stars, a gay marriage, and a movie. Just as Homer sometimes fails to properly appreciate Marge’s buxom, blue-haired beauty, fans of The Simpsons tend to take the show for granted. The series, which begins its 16th season on Nov. 7 (with the annual ”Treehouse of Horror” Halloween-themed episode), has been so funny for so long that it can feel like an inexhaustible natural resource, like comedic tap water. But as a conversation with longtime Simpsons executive producer Al Jean reveals, maintaining the quality of the longest-running sitcom in television history isn’t easy. Here are six facts worth knowing about the new season — and beyond: Liam Neeson voices a priest who helps Bart and Homer consider converting to Catholicism (Homer likes the part with the wine); James Caan visits Bart’s treehouse after he converts it to a junior Playboy Mansion; and Lucy Liu plays a bureaucrat when Homer pretends to be married to Marge’s gravel-voiced sister Selma so she can adopt a Chinese baby. Read More >>>