Hot Tub Time Machine is the best movie I have ever seen that features a hot tub time machine. It's a movie that doesn't promise much which is good because it doesn't exactly deliver much. All four leads do a pretty great job with what they are given and the movie creates a few memorable side characters as well. The basic premise is that after an old friend (Rob Corddry) attempts to kill himself, his two friends (John Cusack and Craig Robinson) along with Cusack's nephew (Clark Duke) go to spend a weekend at an old ski resort that used to be the coolest place when they were younger. However upon arrival they realize that the area is decrepit and no where close to it's awesomeness of yesteryear. Trying to make the best of the situation, they decide to get wasted in the hot tub (time machine!). Once they wake up from their night, they slowly realize what's happened and then they all split off to relive a weekend from their past.
That's pretty much the least important information about this movie. The movie is at its best when the humor comes from the characters themselves but it does unfortunately dive into "OMG, the 80s were sooo funny!" type comedy a little too much at the beginning. The movie really wants to make sure you understand they are in the 80s (giant cell phones!). In fact, the first scene set in the 80s shows so many of these "clues" that it just becomes a joke (the bar they go to has roughly 7 TVs all tuned to defining 80s moments). But that's only a small complaint. I still laughed out loud a lot during this movie and it was mostly thanks to Rob Corddry. He doesn't stray too far from previous characters he's played but he is amazing as the douche bag friend. His character is summed up perfectly in the beginning by Craig Robinson when he states "You know how every group of friends has an asshole. He's our asshole." I still find myself quoting a lot of his lines a week later. The rest of the cast is great as well but Rob gets the MVP star.
For a time travel movie, it obviously needs to set up some rules regarding the time space continuum. I was actually shocked they took so much time to discuss the rules of time travel since it's really just a comedy and not a sci-fi movie but for what it is, it does a better job explaining some things than other "real" sci-fi time travel stories. That's not to say that if you think too hard about the logic that your head won't start to hurt, but it doesn't really matter because you are too busy laughing at the nonsense happening on the screen. I don't want to get into spoilers, but the ending brought up a big philosophical debate in my head which made me like the movie even more. It's not exactly LOST or Timecrimes, but I was pleasantly surprised by the use of time travel in the movie. If you want a fun (but raunchy) comedy, I suggest checking this movie out.