In 1987, when the tone of American comedies was much more innocent than it is today, Chris Columbus made “Adventures in Babysitting,” a moderately enjoyable John Hughes-inspired romp about a young woman (Elisabeth Shue) who took her charges into the big city and got them involved in all sorts of rowdy shenanigans. Now the same story has been rewritten—without acknowledgment, of course—for big-boned Jonah Hill, and in tune with today’s zeitgeist, the innocence is replaced by raunchiness, nastiness, and lots of pop-modern irony. “The Sitter” is Columbus’ movie refashioned for the post-“Hangover” generation. The result is a depressing cascade of gross-out humor, slapstick violence, hipster fast-talk and drug gags, to which are added a predictable streak of sentiment and a dollop of cheap enlightenment.

Hill plays—or pretty much walks through the role of—Noah Griffith, a chubby half-geek, half-know-it-all whom we meet engaged in servicing Marisa (Ari Graynor), whom he’d like to be his girlfriend, in a scene designed to establish the picture’s sniggering, low-brow spirit. Quickly the slacker is dragooned by his mother into babysitting for a couple who have arranged a blind date for her.

Noah’s thus stuck with a trio of difficult children. Slater (Max Records) is a lonely teen on meds for mood swings. His sister Blithe (Landry Bender) is a cute but aggressive tyke who smothers herself in makeup. And they have a recently-adopted Salvadoran brother, Rodrigo (Kevin Hernandez), a surly boy who dresses in camouflage clothes and enjoys blowing up toilets with cherry bombs. Noah intends to keep them at arm’s length for the evening, but a call from Marisa sends them all on a mission to buy some cocaine from wacko dealer Karl (Sam Rockwell).

Naturally things do not go well, and what follows is supposed to be a comedy of frustration that builds in hilarity. Unfortunately, the episodes are alternately crass (one involves an obese clerk in a children’s store who suspects Noah of being a child, another a fellow—played by J.B. Smoove—who winds up with a firecracker smoldering in his crotch), creepy (the visit to Karl’s pad, complete with all sorts of weird attendants), and mean-spirited (a fight with a kick-boxer, another with a hard-nosed black woman).

Between these are inserted the inevitable soft moments—the ones in which the incredibly insightful Noah diagnoses each kid’s problem and resolves it, “Breakfast Club”-style, and they come to see him as a wise big brother. One of these—with Slater—is actually kind of courageous in that it articulates a position against anti-gay bigotry that’s unusual in these kinds of movies, which usually aim for laughs with homophobic throwaways. But for the most part they’re dime-store panaceas. In addition, a sequence between Noah and his standoffish father (Bruce Altman), designed to engender sympathy for the purported hero, falls flat, as does the obligatory romance he develops along the way with a sweet girl (Kylie Bunbury) who’s just right for him (as Marisa just as clearly is not).

“The Sitter” is just as banal an exercise in cliché as its title suggests, but unlike a picture like “The Pacifier,” which followed the same formula but strained to be nice, it embraces every sort of crudeness it can in order to seem edgy. That’s apparently the new normal for director David Gordon Green, who seems to have abandoned his early ambitions as a serious director with “Pineapple Express” and become content to crank out drug-laced goofball comedies like “Your Highness” and this. Hill slides through the picture on his natural affability and motor-mouth skill, but they prove insufficient over the long haul. And though none of the supporting cast get much chance to shine, Rockwell, who worked with Green on one of his interesting early pictures (“Snow Angels”), is stuck with an especially embarrassing role as the alternately wacky and nasty drug lord. James Franco—who was the best thing in “Express” but one of the worst in “Highness”—isn’t actually in the cast, but still doesn’t escape unscathed: Green inserts a clip from the actor’s guest appearance on the ABC soap “General Hospital” as a sort of shout-out. How hilarious.

Advice from this quarter: sit “The Sitter” out.