James Marsden stars as Neal Oliver, a young man who struggles with standing up to his father and choosing a life direction. On his 22nd birthday, he's visited by O.W. Grant (Gary Oldman), who grants Neal's wish to "find an answer for his life." A meaningful road trip ensues, where Neal is exposed to different philosophies and adventures, including a quest to find a beautiful woman (Amy Smart) who has been appearing to Neal in visions.
Interstate 60 contains examples of:
- Be Careful What You Wish For: Almost every character who interacts with O.W. Grant experiences this.
- Black Hole Belly: The first man Neil meets whose wish O.W. granted. He loved eating and wanted to order everything on the menu but was frustrated by the limited capacity of his stomach. He made a wish which he explicitly says seemed to have given him a black hole for a stomach. Now he has to eat massive amounts of food 6-7 times a day so as not to starve and eating has become a chore.
- Courtroom Antic: Neal calls his dynamite-strapped friend Bob Cody to the stand, knowing that the town's shenanigans will lead to Cody starting the timer on his body bomb.
- Deal with the Devil/Magically Binding Contract: Lloyd invokes both of these when Neal accepts the job by having Neal add a drop of blood to his signature.
- Every Car Is a Pinto: Neal's car explodes after it goes over a cliff.
- Girl of My Dreams: Played straight with Lynn.
- Half-Human Hybrid: One proposed origin of O.W. Grant is that he's the son of an immigrated Leprechaun and a Cheyenne Indian Woman. When his land was lost he became a nomad using his magical powers across the country.
- Jackass Genie: OW Grant does this with wishes he considers greedy or short-sighted.
- Maybe Magic, Maybe Mundane: Was Neal's road trip the result of a concussion, dream, or hallucination, or was it supernatural intervention by the only wish-granting entity native to North America?
- Missing Floor: Neal is going to an appointment on the 13th floor of a building where he will learn the answers about his dream girl. One problem: the elevator doesn't have a button for the 13th floor!
- Or Was It a Dream?: After Neal meets Lynn and makes his delivery on Interstate 60, he wakes up back in his normal life. Then, coincidentally, he meets Lynn again at an art show, but she acts as if she's never met him before. However, the painting he made after consummating his relationship with Lynn during his adventure is on display at the art show!
- Road Trip Plot: Neal must travel the mythical Interstate 60 to discover his life's "answer."
- Secret Test of Character: Lynn pulls this on Neal after he rescues her from jail.
- Strapped to a Bomb: Bob Cody lives like this. This way he can instantly (and fatally) punish anyone he catches lying.
- Troll: O.W. Grant highly recommends this as a hobby.
- You See, I'm Dying: Bob Cody, who decides that since he has nothing to lose, he'll strap a bomb to himself and take anyone who doesn't repent of lying with him.