This is an independent film that was released in 2004. I was referred to it by my friend Joe, who seems to have well enough taste in films. Well, it turns out, it was a really, really great movie, and I'd reccomend you head to your local video store and check it out, if you haven't seen it yet.
A very thought provoking and just all-around smart movie, Primer centers on two men, Abe and Aaron, who are down-on-their-luck engineers looking to invent something to make them money on the side from their regular jobs. What was supposed to be a high-temperature superconducter, however, more than excelled their inventiveness... as the two men accidentally create a time machine.
The film focuses on their travels through time over a few days, and its all set in relatively sound physics (i.e., the only scientifically possible type of time travel is travelling into the past and emerging at the same moment you started the time machine). It's just a very, very smart film and I think a lot of you could enjoy it.