Hot Tub Time Machine basically consists of a series of gags that some describe as potty humor. It does contain a few hilarious moments, but overall I thought it was very juvenile and the sight gags often made me feel nauseated.
One funny, raunchy, and nauseating scene relates to fellatio. Run to the dictionary or think of Bill Clinton and his famous remark, "I did not have sexual relations with that woman." In this case, the fellatio is performed by one man on another.
Now to the story line. Three misfits in their 40s who are distressed with their lives decide to visit a ski lodge of their youth. Adam (John Cusack) has just broken up with his girlfriend. Nick (Craig Robinson) is a relatively happily married man, but his dream of a music career with a band has eluded him. Lou (Rob Corddry), who carries most of the film, is an alcoholic and a raging bull always ready to fight. Also joining the three men is Jacob (Clark Duke) who is in his 20s. Jacob, who does not know the identity of his father, is the nerd child of Adam's sister.
The men jump into the hot tub outside their room and find themselves transported back to 1986, when they last visited the ski lodge. We then see them in their earlier personas as well.