In planning his 20-year reunion, Pittsburgh schlub Dan Landsman (Jack Black) aggravates the inferiority complex he’s been nursing since high school. Duping a credulous Luddite boss (Jeffrey Tambor), neglecting a hormone-addled teenage son (Russell Posner), and betraying a patient jovial wife (Kathryn Hahn), Dan contrives an L.A. trip to nab a reunion RSVP from former class cool kid Oliver Lawless (James Marsden), now a pretty-boy Hollywood poseur who works as a set of abs selling suntan lotion. And so begins the farfetched bromantic farce by which Andrew Mogel and Jarrad Paul, the writing team behind Yes Man, make their directing debut. Unexpected developments ensue, including actual hilarity, amazing Black-Marsden chemistry, and a scorched-earth subversion of the default homophobia that’s otherwise so common to movies like this. Meanwhile Tambor very graciously soft-sells one of the film’s several implausible turns, and Hahn handles her hemmed-in role — ultimately she’s the gatekeeper of Dan’s salvation — with characteristic aplomb. A soundtrack full of pop throwbacks sets the mood for unwieldy fragile-ego regression, although there is some cognitive dissonance in that this so-called class of ’94 only grooves to music from a decade earlier. No matter; The D Train only underscores Mogel and Paul’s slyness about the universal absurdity of being stuck in the past.