7. Insidious
An idea for a terrifying horror-based attraction could be to theme it around Insidious. The attraction could be built inside a creepy-looking house, with the queue area taking you through rooms with bloody hand-prints, rocking horses moving of their own accord, creepy writing on the wall and special effects occurring every now and then to make the queuing guests jump. Then, guests could be met by an eerie cast member, informing them that a child has gone missing and they must enter the Further to retrieve said child. They could then be ushered in to their seats, where it goes dark (as if they have fallen asleep) and when they "wake up", they could be taken on a journey (simulated, or a ride, or an actual walkthrough) whereby scary figures jump out at them to scare the living hell out of them. It would be terrifying, and one for only adults and children above a certain age (and certainly not for the faint-hearted), but it would be great fun.