- Actor-Inspired Element:
- The sex scene in the tub with Craig Robinson was Jessica Paré's idea. Because her character was only in the movie for one scene and she agreed to be nude on the film. She explained this in a interview by saying: "I think tits can be funny." Paré also said that this scene was "one of the most entertaining things she's ever done".
- According to Clark Duke, it was his idea for his character Jacob to travel back in time, and find out Lou was his father.
- Awesome, Dear Boy: 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.
- Box Office Bomb: The second film grossed a mere $13 million on a $18 million budget.
- Completely Different Title: The Portuguese title is A Ressaca, or The Hangover, not to be confused with another film with the same title.
- Irony as She Is Cast: Sebastian Stan as the hyper-jingoistic and xenophobic bully harrying the protagonists because he believes them to be Communist infiltrators from the Eastern Bloc. Stan grew up in Romania (which was a Communist Soviet satellite at the time the film is set, and part of the Eastern Bloc) and didn't become a US citizen until he was 20.
- Contrariwise, years later Stan did play a Soviet super-soldier!
- Old Shame:
- For Sebastian Stan. He hardly talks about it in interviews.
- John Cusack does not look back fondly on his role, due to his preferring roles in more serious films. It is the most likely reason why he did not return for the sequel (apart from appearing in one deleted scene).
- Jessica Pare segued from playing roles in respected Canadian indie films like Lost and Delirious and co-starring in the prestigious series Jack & Bobby to spending her entire role in this film naked and having sex with one of the characters, and even being showcased in a redband trailer doing nothing but showing off her large breasts. Her next role after this ... Megan Draper in Mad Men, the same year. Take a wild guess which role she likely isn't going to be talking much about in years to come.
- Revival by Commercialization: The song "Home Sweet Home" by Mötley Crüe received a brief boost in popularity following the release of this film.
- Separated-at-Birth Casting: The boy chosen to be a young John Cusack.
- Star-Making Role: While John Cusack and to a lesser extent Craig Robinson and Rob Corddry were already famous before this film, this movie helped Clark Duke gain recognition.
- Throw It In!: 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.
- Vindicated by Cable: The first film was only a modest hit at best, making only $64 million against a budget of $36 million. However, it was very successful on home video, enough to get a sequel greenlit.
Trivia / Hot Tub Time Machine