Factual error: The famous AFC Championship game that featured "The Drive" took place on January 11th, 1987, while the events of the film took place in 1986.

Hot Tub Time Machine (2010)
Ending / spoiler
Directed by: Steve Pink
Starring: John Cusack, Chevy Chase, Crispin Glover, Rob Corddry, Lizzy Caplan, Craig Robinson, Clark Duke
Lou stands up to the ski patrol guy and takes from him the Russian energy drink needed for the hot tub to send him and his friends back to the present. Adam (John Cusack) says good-bye to April (Lizzy Caplan) and she tells him that they should meet again and that maybe "the universe will join us again some day." The energy drink is poured into the hot tub's controls and everyone except Lou goes back to the present. Back in 2010, everyone's life has changed: Nick is a successful music producer and his wife didn't cheat on him (because in the past he called his wife and told her to not cheat). Adam is happily married to April. Jacob now has a relationship with a father he never met (Lou). Phil (Crispin Glover) had his arm re-attached thanks to some help from the ski patrol guys. Lou is married to Kelly (Jacob's mother). He used his knowledge of the future and made lots of money by inventing Google (now called Lougle) and also by being the singer of Motley Crue (Motley Lue).
Racer X
Trivia: Chevy Chase makes his first appearance; he farts. This goes back to the movie Spies Like Us when he is taking the test and he farts during the test, blaming it on the guy sitting next to him. The guy says, "Excuse me," as everyone looks at him.





Answer: It's just the rule they used for the movie; not a lot of thought was put into the time-traveling rules with the obvious inconsistencies the movie has throughout regarding it, especially in the ending.
lionhead