I won't tell you anything about The Cabin in the Woods. I will just say this: if you like horror movies, you should go see it in the theater. If you like Joss Whedon's stuff, you should go see it in the theater. If you are vaguely interested in either of the above, you should avoid all spoilers and info about the movie as best as you can. Check it out. You won't be disappointed.
If you've also seen it and want to discuss, we can do that in comments below. As you may have guessed, I loved it.