When ratings get low, dish out the high moral dudgeon. “Law & Order” (7 p.m., NBC) may be in its 20th season and no longer among the most-watched, but it still provides its writers and creators an interesting perch from which to comment on the decline of television.

Actor/comedian Jim Gaffigan (“My Boys”) guest stars as Larry Johnson, the adoptive father of 10 special-needs children who discovers his wife’s bludgeoned body on the kitchen floor. After a few investigative dead ends and red herrings, we discover that Larry was competing with another large brood (raised by an “Octomom” wannabe) for a chance to appear on a “Jon & Kate”-like reality show. And that his wife was not too keen on the idea.

Viewers who have been waiting to put Jon Gosselin on trial for crimes against humanity, decency, basic intelligence or whatever will have to settle for spirited bashing of both the morals and the dubious entertainment value of reality television. Of course, to do that, they will have to tune into “Law & Order” at the too-early hour of 7 p.m., a time slot necessitated by NBC’s ridiculous Jay Leno experiment.

We can only hope that “Law” producer Dick Wolf will take no prisoners as this veteran series completes its final season. Maybe they can put NBC honcho Jeff Zucker on trial for the murder of a network.

• “Ugly Betty” (7 p.m., ABC) returns with a two-hour season opener fraught with office cruelty and filled with guest stars. Betty’s first day as an assistant editor coincides with her fashion-obsessed nephew’s first day in high school. Neither day goes well. Look for Lynn Redgrave as the subject of a magazine story that may transcend Mode’s superficial brand of journalism.

“Betty” lays on the soap-opera antics a little too thick and a little too obviously for my tastes. A little like “Pushing Daisies,” the show seems intoxicated by its own arch cuteness.

It can best be appreciated for its visual flourishes and media in-jokes, like Betty’s “2001”-inspired nightmare about the orthodontist and a Perez Hilton-like fashion reporter. Otherwise, this flamboyantly perky series has all of the wit and contrived emotional gamesmanship of a trip back to the seventh grade.

• “Da Vinci Code” novelist Dan Brown sits down with Matt Lauer to discuss his latest “symbology”-related best seller set in our nation’s capital on “Secrets of the Lost Symbol” (8 p.m., NBC).

Tonight’s other highlights

• The Yankees and Angels meet in game 1 of the American League Championship Series (6:30 p.m., Fox).

• Melinda checks into a haunted hospital on “Ghost Whisperer” (7 p.m., CBS).

• Presented without narration, “JFK: 3 Shots that Changed America” (7 p.m., History) presents unseen clips of the on-the-fly coverage of a confusing story that would have lingering consequences.

• Allison can’t tell whether the symbols in her vision pertain to a case or are only the result of her recent surgery on “Medium” (8 p.m., CBS).

• On “Dog Whisperer” (8 p.m., National Geographic), Cesar Millan helps a disabled woman care for her rescued lab-mastiff mix.

• A murder mystery interferes with plans for Adrian’s birthday party on “Monk” (8 p.m., USA).

• Murders closely resemble the plot of a yet-to-be released movie on “Numb3rs” (9 p.m., CBS).