The musical episode: a sign of confidence or the kiss of death? It’s not like “The Neighbors” (7:30 p.m., ABC) wasn’t already a tad over-the-top. A tale of two New Yorkers, Marty and Debbie Weaver (Lenny Venito and Jami Gertz), who are stranded in a sterile New Jersey subdivision populated by aliens trying to pass themselves off as hyper-“normal” Americans. The visitors have even adapted names from the sports pages — Larry Bird (Simon Templeman) and Jackie Joyner-Kersee (Toks Olagundoye).

This sitcom has always sacrificed logic and consistency on the altar of cute one-liners. So why should the musical episode be any different? As the action begins, Larry and Jackie beg their neighbors and all-too-human minders to take them to a Broadway musical. But Marty and Debbie are cranky. So the disappointed alien couple, feeling a bit frisky, decides to bolt the ‘burbs and walk to the Big Apple and take in a show.

Larry and Jackie return deliriously happy and inspired by their first time experiencing the musical comedy genre. This is where the coy production numbers begin and consistency goes out the window. They’ve never seen a Broadway musical, but their homemade version is filled with knowing and snide wisecracks about Fox’s “Glee” and “American Idol.” Apparently it never occurred to them to watch a DVD of “High School Musical” or “Guys and Dolls.” Sorry to sound like Spock on a bad day, but that’s simply not logical — or terribly funny.

Tonight’s other highlights:

• Whitney and Alex’s honeymoon getaway features a surprise guest on “Whitney” (7 p.m., NBC). A repeat (7:30 p.m.) follows.

• A new case seems familiar on “Law & Order: Special Victims Unit” (8 p.m., NBC).

• Manny’s plans don’t include his own birthday party on “Modern Family” (8 p.m., ABC).

• “NOVA” (8 p.m., PBS) explores personalized medicine based on a patient’s genetic code.

• Russell’s son becomes a suspect on “CSI” (9 p.m., CBS).

• An injured Vargas faces disability time on “Chicago Fire” (9 p.m., NBC).

• Juliette embraces her new image with a vengeance on “Nashville” (9 p.m., ABC).

• The squad plans a major raid on “Boston’s Finest” (8 p.m., TNT).

• John mulls retired life on “Southland” (9 p.m., TNT).

• A mission reunites Philip with an old lover, further alienating Elizabeth from their arranged marriage, on “The Americans” (9 p.m., FX).