7. 'Hot Tub Time Machine' (2010)
Probably the funniest time-travel movie ever made: John Cusack, Rob Corddry, Craig Robinson, and Clark Duke head back to the 1980s while at a ski resort, revisiting a time when hair was big, outerwear was neon, and Poison was a big headlining band. (It's also a time when Cusack was a much bigger movie star; the movie sidesteps that.) Best scene: Robinson having sex in a bathtub so he won't disrupt the timeline, weeping because he feels guilty about cheating on his wife, even though she's only nine years old in 1986.