Who knew hand clapping could be the scariest thing you'd ever hear since "They're heee-re..." or "I see dead people..."? Without the use of big-budget special effects, relying on pure imagination, James Wan (Saw) makes a simple sound one of the most jarring things in this old-fashioned, highly effective and deliciously creepy story.

The story, set in 1971, is based on supposedly true events that occurred in the home of the Perron family. It's the same old stuff: weird blinking dolls and clangy toys, shadows, multiple ghosts, a portal to hell somewhere in the basement, a mysterious figure at the heart of it all. The territory is familiar but Wan keeps the unseen just out of focus and that's what so scary: it's what we can't see that extracts the maximum amount of tension from each tortured moment. This is about putting your nerves on the rack and stretching them as far as they can go, not grossing you out with a lot of splatter gore.

The terrorized couple (Lily Taylor and Ron Livingstone) seeks out the help of demonologists, real-life couple Lorraine (Vera Farmiga) and Ed (Patrick Wilson) Warren. All the players in the piece do far more than just pull their weight. Wan smartly cast good actors and actresses who turned in great performances. They aren't window dressing in the story of their own lives; they are fleshed out, three-dimensional people whose lives have broken on the rocks, the same as if they had endured any other kind of tragedy. Farmiga has a way of portraying characters that are fragile yet have a core of strength that belies their wounded nature. Taylor's acting chops really show in an impassioned performance that humanizes her character. It would have been easy to let the movie take over the starring role but the stellar performances are part of what makes the whole movie work.

And it works on every level: the cast, the direction, the setting, the chills that are built up slowly and the frights that come out of nowhere. The movie has achieved cult status for its "R" rating in spite of its lack of gore and blood, simply because audiences in test groups literally found it too darn scary. (Check IMDb if you doubt!) Wan makes you believe that there's something lurking around every corner, or that something's about to happen any second, just with the power of possibility. The responses it triggers are largely emotional and that's why it's already, and will be, a horror classic, a status it richly deserves.