Josh and Renai move their two boys into a hulking old house. When the older son falls into a mysterious coma, Renai becomes convinced that something is horribly wrong. The family flees to a new house, only to discover it wasn’t the house that’s haunted. Genre nerds will have a blast with Insidious, trainspotting the various borrowed genre staples (the big old house, the creepy attic, the eerie rocking horse) and lifts from specific classics (Poltergeist, Psycho, The Haunting). Then again, one of the reasons scary movies scare you is that you know what’s coming -- or, even better, you think you know what’s coming and it turns out you don’t. The Saw team of screenwriter/actor Leigh Whannell and director James Wan have a field day here, mixing and matching and generally going nuts with skilled variations of classic horror tropes, and the result should provoke gripped armrests and flying popcorn in multiplexes everywhere.