UPDATE
Just got back from the movie, and honestly, I loved it.
The whole time through, I was thinking "This reminds me a lot of Donnie Darko", and sure enough, credits come up "RICHARD KELLY" :D
Well anyway, it's a movie that you'll like if you liked Donnie Darko. Also reminds me of "The Monkey's Paw" and "The Nightmare Box" from "Haunted" by Chuck Palahniuk.
The trailer doesn't begin to cover what the movie is actually about. It's really great and I heartily recommend it.