The Gist: Four friends work on inventing useful devices in their free time in hopes of finding something they can sell. In secret, two of them start working on a device that turns out to give them the ability to time travel. What they do with the device and the consequences of their decisions will have ramifications that affect both them and those around them.
Primer is a pretty cool sci-fi movie that targets the brain more than the eyes; in fact, there are virtually no visual effects.
The screenplay, while well constructed, is pretty complex to follow, and given the usually complicated topic of time travel to boot, get ready for a mental workout.
Shane Carruth and David Sullivan are very promising talents (and are both quite easy on the eyes).
The Bottom Line: Primer is not an easy movie to watch because you can't just sit there and mindlessly watch it while you're checking your email, but if you try and follow it, you'll be rewarded with a pretty cool experience.