The film's title is based on the saying "idle hands are the Devil's play-things" or "idle hands do the Devil's work". The film was a critical and commercial failure, grossing a little over $4 million from an estimated $25 million budget.
Lazy stoner teenager Anton Tobias' parents wind up dead on Halloween, with all the clues pointing to him. After killing his best friends Pnub and Mick, Anton realizes that his right hand has become possessed. Unable to control his hand, Anton throws his cat across the street and while searching for it, he encounters his neighbor Molly and the two start a relationship. Anton holds a funeral for his parents and friends. However, Pnub and Mick decide not to go to heaven, returning to their former bodies and rising from the grave.
Meanwhile, a druidic high priestess named Debi LeCure is hunting the spirit responsible for killings across the country. After his hand kills two cops in his living room, Anton cuts it off with a cleaver. Pnub and Mick seek out a First-Aid Kit while Anton traps the hand in a microwave, burning it. Meanwhile, Debi (now along with Randy, Anton's neighbor) hunts Anton down to put a stop to the possessed hand. After sending Molly to the school dance, Anton returns home to finish off the hand. Unfortunately Pnub and Mick inadvertently release the hand. The three then steal Randy's truck and head to the school. Mick and Pnub go to the Halloween dance to watch over Molly, while Anton looks for the hand. Randy and Debi meet up with Anton. Debi explains that the hand will drag Molly's soul into the netherworld. Anton crashes the dance and tries to warn everyone about his hand, but is ignored.
The hand then scalps the band's lead singer and causes a panic. Molly and her friend Tanya (Katie Wright) escape through the vents. They attempt to go through a fan, which they have stopped with Tanya's shoe, but Tanya gets hung on the rope, Molly tries to pulls Tanya off the fan and Anton's hand ends up removing Tanya's shoe, allowing her to be pulled to her death in the fan. Molly then runs into the art room, causing her to get knocked out. Anton enters and fights with the hand while it is inside a puppet but it escapes to the auto shop, where Molly is strapped to a car in her bra and panties, being raised toward the ceiling. Anton, Mick, and Pnub fight with the hand over the controls. Mick finds a mechanic's bong and he and Pnub smoke "for strength". Anton blows some smoke into the hand (still inside a hand-puppet) until it drops the controls and they save Molly. Debi throws a ritual knife into the hand, stopping it in a puff of smoke and fire. She and Randy take off for "ritualistic sex." Anton releases Molly from the top of the car, they go under the car and start making out. In the process of lighting the bong for Mick, Pnub accidentally hits the controls for the car, and Anton is crushed by the car.
In the film's conclusion, Anton is in a body-cast in the hospital, having given up heaven to stay with Molly, and Mick and Pnub are now his Guardian Angels.
The film opened on April 30, 1999, in 1,611 theaters. It grossed $1.8 million during its first week, and then a total of just over $4 million on a budget of $20–25 million, making it a box office flop.
The film was critically panned. On review aggregator website Rotten Tomatoes, the film has a 16% rating based on 55 reviews, with an average rating of 3.4/10. The site's consensus states: "Idle Hands has neither the humor nor the scares to satisfy audiences." Metacritic reports a 31 out of 100 rating based on 20 critics, indicating "generally unfavorable reviews".
Over the years, however, it has acquired cult film status and continues to sell reasonably well on DVD. Jeremy Wheeler at Allmovie.com gave the film a positive review stating: "It's definitely a case of better than you think. This horror comedy is high on gags and giant doses of marijuana... as is the love for gore and decapitated hand insanity to entertain any happy horror fiend."
A soundtrack album for Idle Hands was released through Time Bomb Recordings two weeks in advance of the film, featuring mostly punk rock and heavy metal artists. Though appearing on the album, the songs "Enthused" by Blink-182, "Mama Said Knock You Out" by The Waking Hours, "Bleeding Boy" by Disappointment Incorporated, and "My Girlfriend's Dead" by The Vandals were not used in the film. Chuck Donkers of Allmusic rated the album two stars out of five, remarking that it "befits a combination teen comedy/horror flick that climaxes at a high school dance" and "features songs from over-the-top adolescent favorites".
The film was parodied in the Robot Chicken sketch "Idle Nuts". The sketch has essentially the same plot as the original movie, but involving possessed testicles instead of a possessed hand.