A Very Harold & Kumar 3-D Christmas

Running time: 90 minutes

Rated: R (strong crude and sexual content, graphic nudity, pervasive language, drug use, and some violence)

Leave it to a “Harold & Kumar’’ movie to expose modern 3-D for the tawdry gimmick it is while understanding that’s at least half the enjoyment. Early on in this unnecessary, drug-addled, and very funny sequel, a co-worker (Bobby Lee) of Harold’s turns to the camera, points to the audience, and assures us that the film’s 3-D will be “a-mazing.’’ He’s then pelted with eggs by Occupy Wall Street protesters. Say what you will, but these movies have their fingers on the pulse of the nation.

Or that part of the nation that still gets the munchies. I hate to spoil the fun, but maturity turns out to be the nagging subtext of this cheerfully ridiculous stoner farce. Several years on from their adventures at White Castle and Guantanamo Bay, Harold (John Cho) is married, living in suburbia, and working for the Man. Ex-roommate Kumar (Kal Penn) is still a happy Hoboken pothead until his girlfriend (Danneel Harris) announces she’s pregnant. Adulthood beckons (and about time, since Penn is in his mid-30s and Cho is pushing 40).

Adulthood will nevertheless have to wait another 90 minutes as the two contend with Harold’s angry, Christmas tree-obsessed father-in-law (Danny Trejo - Machete himself), the sex-crazed daughter (Jordan Hinson) of a violent Ukrainian gangster (Elias Koteas), Jesus Christ, Santa Claus (Richard Riehle), and many others. Because the “Harold & Kumar’’ universe seesaws so delicately between the subversively smart and the ineffably stupid, even the lamest jokes get a witty spin - and even the cleverest ideas can turn into groaners.

Since Christmas is the theme, the screenplay strings Yuletide parodies from scene to scene like so many ornamental doobies. At one point, our heroes find themselves transformed into Claymation puppets out of a ’60s TV special; at another, a classic moment from the much-loved “A Christmas Story’’ gets a particularly disgusting reprise.

The woozy strands of “A Very Harold & Kumar 3D Christmas’’ come together about an hour in during the movie’s high point, a 3-D Busby Berkeley-inspired musical extravaganza featuring Harold and Kumar as wooden soldiers and Neil Patrick Harris as - once again - a highly sociopathic version of himself. Yes, Harris died in the second movie. Death has always been a minor inconvenience here.