Danny Donahue (Paul Rudd) and Wheeler (Sean William Scott) are two Los Angeles salesmen for an energy drink, Minotaur. They tour Los Angeles-area schools driving a Minotaur-themed SUV to deliver infomercials disguised as anti-drug speeches. Wheeler loves the job but Danny, on the other hand, hates the job and possesses a constant negative attitude toward life, which results in the collapse of his relationship with his girlfriend, attorney Beth. Hoping to get his life back on track, Danny spontaneously proposes to her; not only does she turn him down, she breaks up with him. One day after making a disastrous sales presentation at a high school, the duo finds that their company truck is being towed away. They protest by trying to drive it away from the tow truck, but end up crashing it into a school statue.Danny and Wheeler are arrested and the judge sentences the two to a 30-day jail sentence. Beth, however, manages to strike a deal with the judge in which they have to log 150 hours of community service over the next thirty days. The judge selects for their community service a big-brother style program called Sturdy Wings, led by Gayle Sweeny (Jane Lynch), an ex-drug addict, who takes an instant dislike to Danny and Wheeler. Aware that their presence at Sturdy Wings is court-ordered she warns them that she won't accept any B.S. from them and that if they fail to carry out their tasks to her satisfaction, she will have them sent to prison. Wheeler is paired up with Ronnie Shields, a foul-mouthed, streetwise miscreant obsessed with boobs who has driven away all the other adults he has been paired with, while Danny is paired up with Augie Farks, a nerdy teenager obsessed with live action fantasy role-playing games.Initially, the pair find their task extremely difficult, with Danny unable to find any common ground with Augie and his narrow interests, and Ronnie taking virtually no interest in Wheeler. After a few days they gradually bond with their respective partners; Ronnie takes an interest in Wheeler's favorite band KISS and discovers that Wheeler shares his obsession with boobs, whilst Danny reluctantly participates in Augie's medieval live action role playing group, "LAIRE". During a Sturdy Wings camping trip, Wheeler uses Danny's Ambien to try to have drugged-out sex with another mentor who instead passes out naked in full view of the other children, Ronnie and Augie cover for their mentors. At the same time, Danny tries to make up with Beth for his mistakes, but to no avail. Beth must commit to the break-up, as she feels it's for the best.Unfortunately, their success is cut short when Augie manages to "kill" the arrogant King Argotron (Ken Jeong) during one of the role playing games, with the latter lying and claiming he killed Augie first. When Danny angrily defends Augie, the King permanently bans them both, causing Augie to cry in front of everyone, including Esplen (Alexandra Stamler), who he has a crush on. Wanting to apologize to Augie, Danny goes to dinner at his house. Augie's mother, Lynette (Kerri Kenney), and her live-in boyfriend, Jim (Ken Marino) are glad Augie has been kicked out of LAIRE and thank Danny for helping that happen. Seeing how unhappy Augie is, Danny criticizes Lynette's and Jim's parenting skills and for not supporting Augie's hobby. Both Lynette and Jim are insulted by this, and Danny is then kicked out of their home. Nevertheless, Danny still defends Augie.Wheeler, meanwhile, takes Ronnie to an adult party in Venice and leaves him unsupervised while he has sex with a blonde he meets at the party. Feeling abandoned, Ronnie walks all the way home by himself.Ronnie's and Augie's parents consequently ask Sturdy Wings to assign them new mentors and Gayle expels Wheeler and Danny from the program, thus failing to meet the 150-hour goal needed to complete their community service . As such, the pair is given a court appointment where they will likely have to serve their thirty days in jail. In the elevator, Danny berates Wheeler for leaving Ronnie behind while Wheeler scolds him about his whining. The two have a falling out and go their separate ways.Wheeler goes to Ronnie's house and gets permission from Ronnie's mother to hang out with Ronnie after he gets out of jail. Meanwhile, Danny looks through his closet and finds the battle attire Augie had given him. Remorseful for his actions, he secretly meets with the LAIRE king to negotiate Augie's readmission where Augie can fight in that afternoon's Battle Royale, the final battle of the year. Danny then sneaks Augie out of his house so they can prepare for the Battle Royal that day but while Danny is visiting, Augie learns that Xanthia, the fantasy "nation" to which he belongs has expelled both Augie and Danny, the former being that Augie is too much of a liability. Danny offers to form a new team with him, but a team must have at least four members.Danny calls Wheeler and asks him and Ronnie to join the battle so that Augie will have enough teammates. Dressed up as the members of KISS and riding in the Minotaur SUV, Danny, Augie, Ronnie and Wheeler arrive ready to fight in the Battle Royale as members of KISS-My-Anthia, a new nation. Augie's parents, Ronnie's mom, Gayle, and Beth come to watch. Near the end of the battle, Augie squares off against the King and kills him in front of everyone. His victory is short-lived as a hidden player, Esplen, attacks and defeats him. Augie's parents, Lynette and Jim, congratulate Augie for his performance and recognize how happy he is when role-playing. In the after-battle party, Augie finally speaks to Esplen, who asks him to be her co-regent and the two kiss. Danny serenades Beth in front of everyone with an improvised version of the KISS song "Beth" and the two reconcile. Gayle, impressed with the pair's efforts, promises to intervene with the judge, with whom she has a long-standing relationship, so that Wheeler and Danny will be able to get their names cleared.