Remember that fantastic Eddie Murphy bit from Delirious where Murphy demonstrates what any black person (but, really, any sensible person) would do when faced with the demons of The Amityville Horror: “Too bad we can’t stay, baby!” Murphy’s routine rang a bell during Paranormal Activity, because for characters Katie Featherston and Micah Sloat (the actors use their real names), it isn’t that easy. Whatever is in their home is haunting them, not the house. Activity’s twist on haunted-house and demon yarns is fresh and creepy, the characters act genuinely (with hyperventilating fear or, in Sloat’s case, stubborn bravado) and the scares are shocking, visceral and cathartic. Activity gets the blood pumping and the mind buzzing. We often leave the theatre only mildly diverted, here you feel defiantly alive.