“Battlestar Galactica: Razor” (8 p.m. today, Sci Fi) offers a movie-length flashback to the early years of the Cylon war and the battlefield decisions that shaped major characters, including Lee Adama (Jamie Bamber) and his father, Adm. Adama (Edward James Olmos).

Like many of the best “Battlestar” episodes, this adventure mixes action with meditations on real-world questions, such as just how far a soldier should go in following orders, particularly when they relate to civilians. Ambitious new officer Kendra Shaw (Stephanie Jacobsen) learns the cost of following her superior and mentor, Adm. Helena Cain (Michelle Forbes), in a quest to become a “razor,” a pure fighter ready and willing to do anything to win.

Fans of the series should not miss “Razor,” and they should pay close attention to the very end, when secrets, or at least hints, about the destiny and purpose of a major character are revealed.

¢ Veteran TV actor Ernest Borgnine stars in the title role in “A Grandpa for Christmas” (8 p.m. today, Hallmark). Borgnine’s crusty character, Bert, has grown estranged from his grown daughter. But after she suffers an accident, he is forced to take custody of his granddaughter, Becca (Juliette Goglia), who has heard only dreadful stories about him. Things begin rather frostily but thaw when Bert, a retired actor, helps Becca rehearse for her holiday pageant.

Borgnine’s six decades on television go back to the medium’s infancy. He appeared on “Goodyear TV Playhouse” in the 1950s, the showcase that produced “Marty” (with Rod Steiger in the role). That drama was adapted for the big screen, and Borgnine won an Oscar in the title role. In the 1960s, he skippered the war comedy “McHale’s Navy.” He was in “Airwolf” in the ’80s and “The Single Guy” in the mid ’90s, and, with “Grandpa,” he appears to be going strong well into the 21st century.

¢ Fans of special effects and dark British whimsy will enjoy the four-hour miniseries “Hogfather” (6 p.m. Sunday, ION), based on a best-selling book by Terry Pratchett. Set in a city in a parallel world that looks much like Dickens-era London, on a winter holiday called Hogswatch that looks very much like Christmas, “Hogfather” combines the whimsical occult elements of “Harry Potter” with traditional figgy-pudding holiday fare. For example, on Hogswatch, a jolly fat man delivers gifts in a sleigh pulled by what looks like a team of wild boar. But things get complicated when a ghostly supernatural “auditor” wants to do away with the cherubic gift-giver.

¢ The surest sign of the holidays has to be a back-to-back airing of the 1983 favorite “A Christmas Story” (7 p.m. and 8:45 p.m. Sunday, TNT). Try not to watch it at least once. If you don’t shoot your eye out, you might find a turkey smiling at you.

Today’s highlights

¢ The voice of Craig T. Nelson animates the 2004 cartoon adventure “The Incredibles” (7 p.m., NBC).

¢ Howie Mandel hosts “Wild 100: Top 10” (7 p.m., Animal Planet).

¢ Jack sacrifices a beloved collection for his career on “30 Rock” (9:30 p.m., NBC).

Sunday’s highlights

¢ Animal Planet offers four consecutive opportunities to catch the beloved 2005 documentary “March of the Penguins” (6 p.m., 8 p.m., 10 p.m. and midnight, Animal Planet).

¢ Tastes like chicken on “Amazing Race” (7 p.m., CBS).

¢ The exploding population of incarcerated Americans is explored on “Prison Nation” (7 p.m., National Geographic).

¢ Lynette embraces her stepfather on “Desperate Housewives” (8 p.m., ABC).