SHOWS FOR YOUNGSTERS AND THEIR PARENTS TOO : Famous alumnus visits ‘Saved By the Bell’; baby polar bears survive the odds in documentary

In this week’s episode of Oscar’s Orchestra (KTLA, Sunday at 8:30 a.m.), called “The Ring Cycle,” Oscar the grand piano finds himself once again battling Thadius Vent, whose mission is to rid the world of music. Oscar battles Thadius for possession of the Ring, which bestows ultimate power on its holder. For ages 5 to 10.

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Klondike & Snow, a Tale of Twin Polar Bears is a heartwarming documentary that allows viewers to witness the heroic efforts of the Denver Zoo’s veterinary staff to save the lives of two polar bear cubs (KCET, Wednesday at 7:30 p.m.). The cubs, abandoned by their mother and left nearly frozen to death, survive after much struggle. For the family.

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Flator, Airhead, Bouncer, Squeeker and L.A. Tex are the Balloonatiks: balloons with human traits. In “Christmas Without a Claus” (Fox Kids Network, Saturday at 7 a.m.), they save Santa from kidnappers. (This animated special replaces “C-Bear and Jamal” this week only.) For ages 2 to 11.

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Mario Lopez’s A.C. Slater returns to “Saved By the Bell: The New Class” (NBC, Saturday at 9 a.m.). Lopez was in the original comedy series for five seasons, 1989-’94. He visits the teen gang’s old hangout, the Max, after it burns downs, and reminisces with the new cast about some of the great times everyone had there. For ages 10-16.

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The Bug Hunt, a short animated film based on 12-year-old Matthew Mehne’s prize-winning story from the Disney Channel’s “Create a Great Story” writing contest, gets a premiere on the cable network (Saturday at 6:45 p.m.). For ages 7 to 14.

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The annual American Teacher Awards, presenting the outstanding skills and talents of 36 elementary and secondary teachers from around the country, is telecast from the Pantages Theatre in Hollywood (Disney Channel, Saturday at 7 p.m.). For the family.