Salma Hayek and Adam Sandler star in Grown

There’s a practice among standup comedians called “emptying the notebook.” It’s a housecleaning exercise in which they get together, read off the jokes that didn’t fly and toss away the index cards to start writing afresh. “Grown Ups” apparently was launched when someone thought they should use the discarded jokes to make a movie.

Uniting the creative forces behind “Paul Blart, Mall Cop,” “The Hot Chick” and “Dickie Roberts: Former Child Star,” the latest offering from Adam Sandler’s production company is “The Big Chill” for morons. This bone-lazy film is a comedy only if you believe Kevin James falling off a rope swing is funny.

Thirty years after junior high, five basketball teammates reunite for a getaway weekend at a lakeside cabin in New England. (“New England” is the onscreen description and an indication of the finely honed screenwriting on tap here). Sandler, James, Rob Schneider, Chris Rock and David Spade bring their families, who consist of problematic wives and troublesome kids.

Salma Hayek, partnered with Sandler, plays a high-powered fashion designer; their kids are overentitled brats who shudder at the notion of drinking unbottled, nondesigner water. Maria Bello, much to James’ chagrin, is still breastfeeding their 4-year-old son. Sweet-tempered Joyce Van Patten plays Schneider’s senior citizen wife; through some miracle of genetics he has two supermodel daughters from earlier marriages. Maya Rudolph is the bossy breadwinner to Rock’s househusband; their pubescent son ogles Schneider’s hottie girls. Spade continues to play the smarmy lothario bachelor.

Longtime Sandler collaborator Dennis Dugan directs to the extent that turning the camera on and off can be considered moviemaking. The cast appears to be rolling with whatever halfhearted notion strikes them in each scene. The guys goof off. The guys hang out. The guys pratfall. The guys pee in public. The guys tease one another about getting old/ fat/ drunk/ pretentious. The film unspools without form or characterization or drive, like a home movie of Sandler and his drinking buddies ad libbing.

The affection the stars feel for each other is clear, but it’s impossible to share it. Their comic styles don’t mesh. Spade’s sarcasm and Rock’s dry wit exist in different comic dimensions from James’ oafish physicality and Schneider’s bug-eyed eccentricity. As for Sandler, he has simply stopped trying.

Thankfully, the film proceeds without the combative anger management issues that propel so many of Sandler’s movies. His most aggressive act is to smack Schneider’s New Age food faddist in the kisser with a dehydrated banana.

There is a climactic basketball game with the friends’ old middle school rivals (including “Saturday Night Live” 1990s second-stringers Colin Quinn and Tim Meadows), but the showdown is a low-stakes affair. Without a real antagonist, there’s no struggle, no goal for the characters.

They’re just killing time onscreen. Slowly and painfully.