The film focuses on several characters. One of the main protagonists, Dean (Justin Long), has been a waiter for four years since graduating from high school, and hasn’t earned a degree during his four years at a community college. When Dean learns from his mother (Monica) that a former high school classmate, Chett (Travis Resor), now has a bachelor’s degree in electrical engineering, he begins to rethink his direction-less life. Dean’s lecherous friend and co-worker, Monty (Ryan Reynolds), is in exactly the same situation, but has accepted that his future lies with the restaurant, Shenaniganz. Monty is put in charge of training Mitch (John Francis Daley), a newly hired waiter who is constantly interrupted throughout most of the film. Also working with Dean is Calvin (Robert Patrick Benedict), a hopeless romantic who cannot hang onto a relationship, and Dan (David Koechner), the uptight manager who is grooming Dean as his protégé. Rounding out the staff are 17-year old hostess Natasha (Vanessa Lengies), abrasive waitress Naomi (Alanna Ubach), waitress (and Monty’s ex-girlfriend) Serena (Anna Faris), Dean’s girlfriend and fellow waitress Amy (Kaitlin Doubleday), stoner bus-boys T-Dog and Nick (Max Kasch and Andy Milonakis), head chef Raddamus (Luis Guzman), the insane, unsanitary chef Floyd (Dane Cook), and the pensive and philosophical dishwasher Bishop (Chi McBride).
The waiters preoccupy themselves with endless gossip, complaining about the customers, seeking covert revenge on particularly rude patrons, and playing a special kind of game which involves flashing genitalia at a fellow worker (the “Penis Showing Game”). Each employee has his or her own problems and stories, which are interwoven with the ebb and flow of business.
Minutes before the restaurant closes, however, Chett and his girlfriend come in for dinner and leave Dean a hefty tip out of pity. This prompts Dean to quit his job — turning down an assistant manager position Dan offered him at the beginning of the film — and seek a more promising future.
When the shift ends, the staff head to a party at Monty and Dean’s house. At the party, Monty is able to resist having sex with Natasha (although he says they will have sex the following Wednesday, when she will be 18), Calvin attempts to fix his relationship problems, and Mitch bashes most members of the staff after being constantly interrupted throughout the day. He concludes by giving them all The Goat from the “Penis Showing Game,” for which Monty declares him a god and swears his undying allegiance to him. The film ends with the staff talking about the incident with Mitch, Dan showing up at a disgruntled customers’ house after Natasha gave him the wrong address to the party, and the hip-hop music video debut of Nick and T-Dog.