When the boys travel back in time and open their suitcases to find Adam's filled with drugs, Jacob asks "Who are you, Hunter S. Thompson?" John Cusack was actually very good friends with Hunter S. Thompson.
In an interview, John Cusack stated that he made his decision to join the cast of this film almost entirely based off of the title.
As a fun inclusion for the fans, the light-blue Chevy pickup with the "sidestep" bed is just like the one the kids in "Red Dawn" used to escape into the woods, and "Red Dawn" is also the movie that inspires Blaine, the chief antagonist, to believe that the time travelers might actually be some kind of "21 Jump street communist spy battalion type dudes."
Craig Robinson came up with the Michael Jackson joke used on the trailer, as well as the "It must be some kind of hot tub time machine" line that he deadpans directly into the camera.
One of the clips shown on TV, inside the ski lodge, is a Saturday Night Live sketch by Eddie Murphy. The classic skit has Murphy looking, singing and acting just like the legendary James Brown getting into his hot tub.
Jacob makes a reference to the Stephen King novel The Shining. "I'm gonna make a prediction right now. One of us is gonna start writing a novel, and then we all get snowed in, and then Lou's gonna axe murder all of us." John Cusack previously starred in the movie 1408, which was based on a short story by Stephen King.
During the sex scene between Lou and Kelly, Lou shouts "Droppin' Loads!!" upon orgasm. This is a reference to porn star Nick Manning's signature catchphrase.
When they're on the mountain, a guy skies past talking on a cell phone and asks "where's my $2.00?", a reference to the deranged skiing paperboy in Better Off Dead... (1985), starring John Cusack
Crispin Glover, who plays the bellhop at the hotel, also starred as George McFly in Back to the Future (1985), another time-traveling movie that takes place partially in the mid-1980s. Additionally, he lost his arm in an accident whose cause isn't shown until the end, just like the cause of his son Marty's hand injury isn't explained until the end of Back to the Future III.
After arriving in the past, John Cusack's character pulls a Fishbone T-shirt from his suitcase. Cusack is a known fan of the band, and there have been references to them in several of his other films.
When the guys first realize they're in the 80's and images are flashing up on the TV, there is one shot of Chevy Chase from his appearance in a Paul Simon music video "You Can Call me Al" from 1986 which is the year the movie is set. Chase plays the repair man in the movie.
During the closing credits, the last entry under the cast says "and introducing William Zabka". This is obviously an inside joke as Zabka has been acting since the early 1980s.
Writers Sean Anders and John Morris were originally slated to direct until they were replaced by Steve Pink, a personal friend of John Cusack.
Towards the end of the movie, a credit/debit card is shown close up - a blue Capitol Federal Savings card. That is a Kansas bank based in Topeka, Kansas.
Months after the film had wrapped principal photography, it was decided that additional scenes were needed. The scenes with William Zabka were filmed just a few months before the film was released.