Arthur: It's Only Rock 'n' Roll (PBS, check local listings): Arthur is back in his second prime-time special featuring the Backstreet Boys. It's a little convoluted for a cartoon, but the music is fun for the younger set.
The Biographer: The Secret Life of Princess Di (CBS, 9-11 p.m.): It may sound a bit cheesy, but this engaging film about Diana's official biographer, Andrew Morton, and his relationship with the princess is rather sad and touching. Newsreel footage helps create verisimilitude. But it's the performances by Paul McGann, Faye Dunaway, and Hugh Bonneville that give real grit to the tale.
The Art of Darkness: A Night Gallery Retrospective (Mystery Channel, 8-8:30 p.m.): A new documentary introduces a 24-hour marathon of the 1970s series. Leonard Nimoy, who directed one episode and starred in another of the supernatural series, explains in fine detail how host Rod Serling and his producer gave Steven Spielberg, John Badham, and Jeannot Szwarc a leg up in the business. They also gave established actors like Pat Boone, Phyllis Diller, and Joan Crawford the opportunity to shine in the Gallery.
Caught in the Crossfire Arab-Americans in Wartime (PBS, check local listings): Three Arab-Americans are profiled in this important documentary: a correspondent for an Arab newspaper, an Arab Lutheran pastor, and an NYPD officer who was stationed at ground zero after Sept. 11.
Wild TV (PBS, 8-9 p.m., Part 2 Sept. 12): Wali Collins hosts the two-part program that takes us on a trek to check out the wildlife in our own surroundings. Urban naturalists explain wildlife in the city, a young entomologist looks for bugs in a typical backyard, feral parakeets thrive, and teenagers show us how to feel at home in the woods.
The Adventures of Jimmy Neutron, Boy Genius (Nickelodeon, 8:30 p.m.): Jimmy was nominated for an Oscar last year. He now makes his home on the small screen. Episode 1 finds Jimmy complaining that being smart is no fun. He invents a machine to make him, well, less intelligent. But when a meteor threatens Earth, only Jimmy can save it.