Cartman's worst nightmare comes true - hippies invade South Park in droves and start a music festival, and it's up to Cartman, running a hippie extermination business, to lead a resistance against them.
This episode contains examples of:
- A Day in the Limelight: Chef, whose role in the show had been increasingly diminishing for the past few seasons, gets one last big role in this episode before being Killed Off for Real in the Season 10 opener.
- Artistic License – Music: Cartman claims Slayer is a death metal band. Slayer was actually a highly influential Thrash Metal band, though they have inspired many death metal acts.
- Black Dude Dies First: Parodied. Cartman tells the townspeople he needs "a black man that can sacrifice himself in case something goes wrong". Since Chef is the only black guy around, he agrees. Later on when the drill stalls, Cartman starts acting as if Chef has volunteered to sacrifice himself to fix it at the risk of his life. Chef begrudgingly goes out to fix it and does so without dying.
- Bumper Sticker: "My karma ran over your dogma."
- Call-Back: This was not the first time Cartman expressed his hatred for hippies, as he has done so in "Weight Gain 4000" several years prior, as well as "Good Times with Weapons" last year.
- Did Not Think This Through: Mayor McDaniels signs off on the hippies' music festival thinking such a large event would bring in some money for the town's economy. Cartman points out that hippies don't have any money to spend and she's effectively doomed the town. She later realizes her error.
- Driven to Suicide: After seeing the negative effects of the hippies on the town, Mayor McDaniels shoots herself in the head. Subverted, however, as she survives, and is later seen with a bandage around her head.
- Drill Tank: The Hippie Digger.
- End of an Age: This was the last episode of the show to feature Isaac Hayes recording original dialogue as Chef. He had been there since the series began, despite his character slowly getting Demoted to Extra at that point and he left after the episode "Trapped in the Closet", due to it mocking Scientology with Hayes himself being a Scientologist. Chef was then killed off in the next season premiere using Isaac Hayes’s earlier recordings. While Chef does appear in a few more Season 9 episodes after this, he doesn't speak in them.
- Evil Is Petty: What does Cartman want for saving the town from the hippies? Getting his own remote-control Tonka truck, preventing Kyle from ever owning one, and forcing Kyle to watch him play with it. It isn't really evil for him to save the town from being taken over by hippies, but it's still very petty.
- Full-Circle Revolution: Stan, Kyle, and Kenny realize the hippies' views are complete bullshit when they propose creating a radical commune that basically amounts to a normal town.Hippie: We'll have one guy who like, who like, makes bread. A-and one guy who like, l-looks out for other people's safety
Stan:... You mean a baker and a cop? - Former Teen Rebel: Randy and Sharon were hippies in the 60s and went to Woodstock. They both have the same flashback of them as crazy stoners screaming and vomiting from acid overdose and having sex in public... and both immediately become worried that Stan will become that if he stays at the festival.
- Godwin's Law: The hippies constantly refer to corporations as "little Eichmanns", a reference to UCB professor Ward Chuchill's controversial essay regarding the victims of the 9/11 attacks.
- Ignored Expert: Cartman knows everything about hippies and correctly predicts that they'll take over the town unless he deals with them immediately. No one believes him...and then everything he warned them about starts coming true.
- Inside a Wall: During his inspection of the old woman's house at the beginning of the episode, Cartman finds a hippie inside one of her walls. Even the hippie isn't sure how he got in there.
- I Warned You: After trying to maintain the hippies and warn the townsfolk, Cartman gets ignored and thrown in jail for abduction. When the hippies actually start to take over, the rest of the town is left having to kiss up to a naturally very sour Cartman.
- Jerkass Has a Point: Cartman turns out to be right about the hippies being a threat to the town's existence and that they need to get rid of them.
- Know-Nothing Know-It-All: The "college know-it-all" hippies. Their commune proposal basically amounts to a normal town.
- My God, What Have I Done?: Mayor McDaniels says the last 4 words of this trope when she realizes what approving the Hippies' Music Jam Festival has done to South Park, leading her to shoot herself in the head... And survive afterwards.
- Randy and Sharon have a simultaneous one when flashing back to their time at Woodstock puking from too much acid, then having sex in it... and immediately realized that was the very environment they now know Stan went to. Randy, in a surprising display of care for his family, immediately runs off to save him.
- No Celebrities Were Harmed: The band on stage at Hippie Jam Fest are caricatures of the members of Phish, particularly the red-headed, bearded, and bespectacled lead singer, who resembles Phish's own singer and guitarist Trey Anastasio.
- Pleasure Island: Stan, Kyle, and Kenny are at first interested in the hippie lifestyle, and they take up marijuana-smoking and guitar-playing. But then, they start to get bored, become sick from all the smoke, and realize that the views espoused by the hippies are total bullshit, and when they try to talk the hippies into actually doing something about the multinational corporations and capitalism they claim to hate, all they can get out of them is an enthusiastic agreement to try to change the world via the power of song. They try to leave right then, but the concert crowd has become so large and dense that they can't move.
- Properly Paranoid: Cartman's hatred of hippies manages to save the whole town from becoming Hippie Capital of the World.
- Shout-Out
- Cartman's exterminator outfit is styled like that of the Ghostbusters.
- Cartman's speech to the town board parodies The Day After Tomorrow.
- The plot of Cartman drilling into the hippie crowd parodies The Core.
- The four-member jam band kicking off the festival resembles the band Phish.
- The scene where Cartman uploads a Slayer CD into the loudspeakers parodies the uploading of the computer virus from Independence Day.
- Smart Ball: Cartman, of all people. After all, he's considered to be an Evil Genius in the later seasons.
- Strawman U: The main group of hippies has a University of Colorado-Boulder bumper sticker.
- Suddenly Always Knew That: Cartman says he'll need a team of three people for his drill: a scientist, an engineer, and a "Black person to sacrifice himself in case something goes wrong." While Randy's been a scientist since the show's beginning and Chef is one of the only Black people in the town, there seems to be no one to fill the second position—until Linda Stotch suddenly announces that she's an engineer and can thus complete the group. There'd never been any indication that Linda was an engineer before this moment.
- Take That!: The entire episode is a giant middle finger towards hippies, portraying them as lazy and incompetent slackers who prefer to get stoned at jam band festival instead of actually doing something productive against the corporations and environmental damage they claim to be against.
