undeadcow: Maybe I'm jaded but I don't consider Cabin in the Woods to be that scary; it's more of a satire.
Yeah I'd go with satire, if they wanted it to be horror they wouldn't have revealed the whole story a few minutes in. It's a shame, I think it would have played out much better if they revealed all that to the viewer along with the characters (course then it'd be more of a horror).
As for recommendations;
I really liked Apollo 18, IMO it's a very good found footage style horror movie with a unique setting; it's set inside the fictional Apollo 18 and on the moon, so it's spacey, but nothing sci-fi like most space horrors tend to go.
The first Paranormal Activity, the sequels are more of the same but each one suffers from the previous movies' sequel bait ending which I doubt the makers really think through. The overarching mystery/story also falls flat and goes a bit silly by the end of 4.
Devil. I watched this on the weekend, it has an interesting premise being stuck in an elevator with the devil. I mention it only because it has a mystery as to which person is the devil and why they're here, which is something the OP might enjoy. However I felt it relies a little too heavily on cutting to black and making noises while something completely awesome is happening.