Like fruitcake and stuffing, holiday movies like “The National Tree” (7 p.m., today, Hallmark) must follow a certain recipe. Take a handsome widower (Andrew McCarthy) still grieving for a woman described a a “special someone” who died decades ago. Add a postcard-perfect Oregon town, home to said widower and fresh-scrubbed teen son named Rock (Evan Williams) given to words no harsher than “awesome.”

Blend in a backstory, told on videotape, about a tree being planted the day Rock was born and add an even more audacious tale about that very tree being chosen to replace The National Tree, located right next to the White House, following a fateful lighting strike on its hallowed predecessor.

Introduce a fetching arborist (Kari Matchett) who’s a little too eager to procure the big evergreen, despite its emotional value to the wounded dad. Shake all of these ingredients in a snow globe of sentimentality, and you’re well on your way to cooking up something for Hallmark.

• The Syfy Network spends the entire weekend airing its Saturday-night specials, grade-Z shockers with titles like “Mega Shark vs Giant Octopus” (4 p.m., today). Saturday’s marathon runs from “King of the Lost World” (8 a.m.) to “Dragon Storm” (2 a.m.), resuming on Sunday with “Arachnid” (8 a.m.) through “The Monkey King, Part II” (2 a.m.). Enjoy.

• Viewers may be forgiven for confusing movies called “A Dog Named Christmas” (8 p.m., Sunday, CBS) and “The Dog Who Saved Christmas” (7 p.m., Sunday, ABC Family). I’ll give you a hint: One features Mario Lopez. And for maybe the first and only time in my life I can declare: the one with Mario Lopez is a little less obvious.

Audiences will react to “A Dog Named Christmas” with either tears or groans, for its efforts to tug the heart-strings are as blatantly obvious as anything I’ve ever seen. (And yes, this is coming from the guy who just sat through “The National Tree.”)

Young Noel Fisher stars as a mentally challenged teen who is befriended by a big yellow Lab whose destiny (or “journey”) was to find the boy and teach him the special healing power of canines. Once illuminated, our hero sets about finding homes for abandoned dogs just in time for the holidays.

You might feel heartless dismissing this as “Forrest Gump Meets Marley & Me on Christmas Morning,” so allow me to do it for you.

For its part, “The Dog Who Saved Christmas” combines “Home Alone” with “Look Who’s Talking.” Lopez provides the voice of Zeus, a less-than-efficient guard dog who saves the family Christmas from inept burglars. Dean Cain, who has been in many movies like this, also stars.

Today’s highlights

• The voices of Ben Stiller and Chris Rock animate the holiday special “Merry Madagascar” (7 p.m., NBC).

• A “retired” superhero (voice of Craig T. Nelson) returns to action in the clever 2004 animated comedy “The Incredibles” (7:30 p.m., NBC).

• Robin tells a lie to honor his dying father on “Robin Hood” (8 p.m., BBC America).

• Scheduled on “48 Hours Mystery” (9 p.m., CBS) child abduction.

Sunday’s highlights

• Bob Saget joins Tom Bergeron for the 20th-anniversary celebration of “America’s Funniest Home Videos” (6 p.m., ABC).

• Springfield puts a witch (Neve Campbell) on trial on “The Simpsons” (7 p.m., Fox).

• Excess is exactly the point of “15 X-Treme X-Mas Decorations” (7 p.m., FLN).

• “Behind the Magic: The Holidays at Disney” (7 p.m., HGTV) documents a theme park’s decorations.

• The 25th Anniversary Rock and Roll Hall of Fame Concert (7 p.m., HBO) offers four hours of musical highlights of performances by Jeff Beck Band, Crosby, Stills and Nash, Aretha Franklin, Metallica, Paul Simon/Simon and Garfunkel, Bruce Springsteen and the E Street Band, U2, Stevie Wonder and others.

• Rebecca hides a vital secret from Justin on “Brothers & Sisters” (9 p.m., ABC).

• Five tribesmen from a remote South Pacific island make a 5,000-mile voyage of discovery across North America on “Meet the Natives USA” (8 p.m., Travel), airing every Sunday through Dec. 20.