A friend who saw The Cabin in the Woods said it more succinctly than I ever could: "I think it's my favorite episode of Angel!" (For those who have lives: Angel is the spin-off of nerd god writer/director Joss Whedon's Buffy the Vampire Slayer TV show.) Cabin co-writer and director Drew Goddard worked with Whedon on Angel, a series that often toyed with fantasy and horror conventions, and so there's a good chance that Cabin began as an Angel episode pitch that was deemed too good to waste on network television.
It is a great idea. A bunch of kids (well, movie kids, which means young-looking hot people in their 20s) head to a cabin in the woods despite encountering an over-the-top hillbilly who prophesies doom. All the while, they're observed by a mysterious team of nerds (headed by the ever-delightful Bradley Whitford) that understands there's a formula to this kind of thing. Soon enough, there is murder and mayhem and intrigue, and to tell you too much more about the plot would be a crime—part of the giddy pleasure of Cabin is sitting through the twists and turns without much foreknowledge.
So let me just tell you instead that this is a well-put-together film. The actors all hold up their end of the bargain. Chris Hemsworth, as the alpha male, shows the same likable hotness that got him cast as the godly lead of Thor (Cabin was actually made before Thor and was shelved for a few years due to studio bankruptcy; happily, it still feels fresh). The script is witty. There are homages to hundreds of horror films, but Whedon and Goddard managed to find something new hidden in all the self-aware shout-outs, too. Cabin is not going to change horror cinema for the next decade, the way the Scream franchise did, but it's great fun, an entertaining flick that rewards you for wasting your life on all those awful slasher movies.