HOT TUB TIME MACHINE was a pleasant surprise in several ways. Thirty minutes into the film I was almost ready to give up. I don't expect much from a comedy, only a laugh now and then. It wasn't happening. However, it turns out that I was wrong, it wasn't so much a comedy as a dramedy. It gets better as it goes along. There aren't that many big laughs, but the characters do get more interesting. At first I was turned off by the one-dimensional characters, but Rob Corddry especially gives a great performance, which I did not at all expect. John Cusack is always good and Clark Duke was also good in his role.
The script has a lot of funny references to other time-travel movies, most notably BACK TO THE FUTURE, including a recurring cameo by Crispin Glover. It's a smarter movie than it seems at first, and in the end enjoyable. Definitely more of a guy movie though.