A romantic comedy that inspires words like “endearing” and still maintains a bracing sense of real life and occasional raunch, “Gavin & Stacey” (8 p.m., BBC America) returns for a third season.

While “The Office” and “Modern Family” do a wonderful job with absurd irony, American sitcoms have long since given up the notion of love at first sight. Who watches repeats of “Dharma & Greg” anymore? But “Gavin” takes the story of two smitten people and works them into a large, cracked social canvas. Their long-distance romance from Essex to Wales, and accompanying cultural clashes, has given way to marriage. Gavin (Mathew Horne) now feels a bit out of sorts after taking a corporate job in Cardiff, Wales.

The first act of the season opener threatens to become “The Office” as Gavin tries to embark on corporate orientation but finds himself constantly interrupted by phone calls and visits from his eccentric friends and family. But we’re soon whisked off to a Christening ceremony for his friend Smithy’s (James Corden) baby, the one he had with the audaciously demanding Nessa (Ruth Jones) before she ran off with her new boyfriend, whom she begrudgingly allows to call himself her fiance. This messy situation, and the fact that Nessa insists that everybody else cater her party, are only the beginning of major complications. And when the elderly pot-smoking lady from down the street fails to bring a salad, all heck breaks loose.

“Gavin & Stacey” projects such an infectious sense of young love and youthful foolishness that I found it easy to overlook the many obscure references to U.K. pop culture that sailed right over my head. I dread the day when some American broadcaster tries to remake this sitcom, a critical hit on British television. Much like the Welsh language soap operas that leave Gavin baffled and homesick, many of the charms of “Gavin & Stacy” remain untranslatable.

l Further proof that the sitcom is still alive and kicking can be found on the ensemble comedy “Party Down” (9 p.m., Starz), set in the Hollywood catering scene. So far this season, the company of acting has-beens, wannabes and writers of unsold screenplays have worked at a prestigious preschool charity auction, a backstage party for a bored rocker and the most depressing “orgy” ever captured on screen. Tonight, a funeral reception unravels when the mistress of the guest of honor upstages his family.

Tonight’s other highlights

• A spirit who summoned Melinda’s help turns out to be anything but dead on “Ghost Whisperer” (7 p.m., CBS).

• West Dillon’s loss is coach Taylor’s gain on “Friday Night Lights” (7 p.m., NBC).

• Zod unleashes his forces on the season finale of “Smallville” (7 p.m., CW).

• An animal rights activist vanishes on “Medium” (8 p.m., CBS).

• Strangers encounter dubious and dangerous behavior on “Primetime: What Would You Do?” (8 p.m., ABC).

• The Alpha team awaits word on the fate of one of their own on “Miami Medical” (9 p.m., CBS).

• Jake Gyllenhaal appears on “Friday Night With Jonathan Ross” (9 p.m., BBC America).

• “Undateable” (9 p.m., VH1) wraps up its five-night, 100-item catalog of social offenses.