Nimrods

On December 20, best friends Tommy and Fred ditch the last day of school before winter break. Both are passionate fans of Green Day and dream of becoming successful musicians with their band, the Analog Dogs. Tommy lives with his older brother Wayne and their mother. Their drummer, Chad, is more cautious and reserved than the other two.

After the boys fail to sneak into a Green Day concert in their hometown, they continue looking for a way to see the band perform live. Around Christmas, Tommy receives his father's old jacket and an 4-track recorder from his mother, further encouraging his interest in music.

Wayne's best friend, Keith, later plays a prank on Tommy and Fred by convincing them that the Analog Dogs have been chosen to open for Green Day at a New Year's Eve concert in Los Angeles. Believing the opportunity is real, Tommy and Fred decide to make the trip to Los Angeles. They take Wayne's car without permission, even though Tommy does not have a driver's license. Chad initially refuses to join them after realizing that the supposed opportunity may be a prank.

The journey quickly becomes chaotic. Tommy loses his phone, and the boys mistakenly put diesel fuel into Wayne's car, leaving them stranded. After discovering Chad's emergency credit card, they use it to help pay for their journey. They enter a small local music competition in an attempt to win money, performing with the Analog Dogs (winning the contest, but upon revealing they were high school students, were subsequently disqualified). When they are unable to get Wayne's car working, they eventually take an ice cream truck and continue toward Los Angeles.

During their trip, Tommy and Fred encounter Olivia and her sister, who stop them while looking for ice cream. They later arrive at a venue called the Hole, where the Analog Dogs perform "Freaking Out". Fred also takes mushrooms that Keith had hidden in Wayne's car, causing him to experience strange hallucinations.

Chad becomes increasingly frustrated with Tommy and Fred's behavior and begins to question his place in the band. Feeling that he does not fit their idea of being "punk rock", he leaves the Analog Dogs. Tommy and Fred continue their journey and eventually stay at the Lincoln Inn, whose suspicious manager initially appears helpful. The manager later reveals himself to be dangerous, forcing Tommy and Fred to escape.

After the two friends have a serious argument, they realize how much they depend on each other. Chad eventually decides to rejoin them. His mother refuses to help them reach Los Angeles, but Chad changes his mind after realizing how important the journey is to his friends. He takes his mother's van and drives to Los Angeles.

The three friends finally reach the Green Day concert and attempt to sneak inside. Chad disguises himself as the venue's mascot while Fred uses VIP passes to gain access. Tommy is caught by security, but the friends manage to get close to the stage. Wayne eventually finds Tommy and admits that the invitation to open for Green Day was a prank. Despite the deception, the boys remain at the concert. During Green Day's performance, Fred is unexpectedly invited onstage to play guitar with the band. The experience inspires the Analog Dogs to take their music more seriously.

After the concert, Tommy, Fred, and Chad learn that Green Day has heard the Analog Dogs' song "Bored" and enjoyed it. Green Day offers the young band an opportunity to perform and record their music, giving the Analog Dogs a chance to pursue their dream of becoming a real punk-rock band.

On their way home, with Wayne driving the minivan, they return to the Hole where Tommy reconnects with Olivia, and he and Wayne's mother join them.