"Boffo! Tinseltown's Bombs and Blockbusters," 6 p.m., HBO. Rarely has a documentary said so little yet been so entertaining. "Boffo" mainly says movie people can never be sure. "Jaws" and "Titanic" were deemed sure failures, then broke box-office records. Sure hits sagged. "Training Day" scored in the U.S. and collapsed everywhere else. Several historic epics did the reverse. You'll be dazzled by the intellect and humanity of George Clooney, Richard Dreyfuss, Penny Marshall, studio chief Tom Rothman and others. Their corner of Hollywood is an optimistic space.

"It's Always Sunny in Philadelphia" season opener, 7 p.m., FX. The first season was made by unknowns on a micro-budget. The show adds stars here but keeps its ragged charm. Dennis and Kaitlin learn that their dad (Danny DeVito) is leaving their mom (Anne Archer) and giving away his money. The part that concerns them is "giving away money." Not since "Seinfeld" have central characters been so self-centered and politically incorrect.

OF NOTE

"Look, Up in the Sky! The Amazing Story of Superman," A&E, and "The Science of Superman," National Geographic Channel; both 6 p.m. As the new Superman movie nears, two channels screen documentaries. On A&E is a two-hour history; National Geographic has a one-hour show, examining the plausibility of the Superman tales.

"Gameshow Marathon," 7 p.m., CBS. It's time for the championship. The finalists play "Family Feud," which is one of the better choices for pure gamesmanship.

TONIGHT ON KHNL NEWS 8

The Honolulu Advertiser celebrates 150 years as Hawai'i's oldest newspaper. All week long, KHNL News 8 is taking a look at some of the papers' milestones in coverage. Tonight, how The Advertiser covered a string of murders in the 1980s that many say was the work of a serial killer. Minna Sugimoto reports tonight on KHNL News 8 at 6 and 10.