Plot
In 1978, childhood friends Lenny Feder, Eric Lamonsoff, Kurt McKenzie, Marcus Higgins, and Rob Hilliard win their junior high basketball championship and celebrate at a lake house with their coach Robert "Buzzer" Ferdinando. Thirty years later, in 2008, Lenny is a wealthy and successful Hollywood talent agent, married to fashion designer Roxanne, and has three children: Greg, Keith, and Becky; Eric claims to co-own a lawn furniture company and has two children: Donna and Bean, with his wife Sally still breastfeeding the latter; Kurt is a stay-at-home father and has two children: Andre and Charlotte; his wife, Deanne, is pregnant with their third child, and her mother Ronzoni lives with them; Marcus is a slacker and lothario; and Rob is married to his much older fourth wife, Gloria, having had a daughter with each of his previous wives.
When Buzzer dies, the five friends reunite for his funeral in their hometown with their families. Lenny rents a lake house in the same town for everyone to stay over during the Fourth of July weekend, though his family is leaving early to attend Roxanne's fashion show in Milan. He pushes his boys to play outside and runs into his childhood opponent Dickie, who claims Lenny's foot was out of bounds when he made the winning shot and has been obsessed with getting a rematch to rectify the perceived 'mistake'.
As the friends spread Buzzer's ashes, Rob breaks down over his failed marriages and reveals that he has invited his estranged daughters Jasmine, Amber, and Bridget to visit. The men then play "arrow roulette", shooting an arrow straight into the air, and it ends up striking Rob in his foot, causing him to snap at Gloria for suggesting a holistic healing method for his injury. The next day, Lenny is thrilled to find the kids playing with cup-and-string telephones, but Roxanne, realizing the positive impact the weekend is having on their children, tells him to cancel their Milan trip and decide to stay at the lake instead.
Everyone visits Water Wizz, where Marcus flirts with Jasmine and Amber after buying them skimpy bikinis, and Eric teaches Bean to drink cow's milk. The families cause chaos throughout the park: the wives attract a bodybuilder and jeer at his high-pitched Canadian accent; Rob assaults a slide attendant when he insults Bridget, and Eric ignores Donna's warning about a chemical in the pool that turns urine blue. At the zipline attraction, Lenny's group meets up with Dickie, accompanied by his son, his former teammates, and his friend Wiley, who is then severely injured after crashing into a shed while sliding down the zipline using his feet.
The next day, Rob attacks Marcus, mistakenly believing that he slept with Jasmine, and Marcus admits to feeling insecure compared to his friends. Everyone tells the truth about the state of their lives: Roxanne confronts Lenny for canceling their flight to Milan before they left home, and he explains he wanted their family to have a normal vacation and to rein in his children's disrespectful attitudes; Deanne confronts Kurt for spending time with the Feders' nanny Rita, but Kurt retaliates by pointing out how she underappreciates him; Eric reveals that he was laid off from his job and was showing off the whole time to avoid humiliation; and Rob admits that everyone knows that he wears a toupee. Gloria helps everyone reconcile, and Lenny and Kurt offer to help Eric start a new business.
On their last day at the lake house, Lenny and his friends agree to do a rematch of basketball against Dickie, Robideaux, Muzby, Tardio, and Malcolm. The game culminates in Lenny and Greg facing Dickie and his son, but Lenny misses the game-deciding shot. As the families watch the Fourth of July fireworks, Lenny tells Roxanne that he deliberately let Dickie's family win to get him off his case and felt that his own family needed to know what losing feels like. Meanwhile, Marcus plays another game of arrow roulette and which causes everyone to run away, with Wiley, who is wearing a full-body cast from the pool incident, getting his foot struck by the arrow.
