I was probably about 10 the first time I picked this up. Then I read it a squillion times. Now I just read it again, as an adult, and I'm pleasantly surprised how well it holds up. 5 teens thrown into a room with nothing but stairs, as far as they can climb in any direction, plus one landing with a little machine on it. The machine will dispense food occasionally, if the teens do exactly what they're supposed to--a series of coordinated movements, from a complicated dance to assaulting each other. But maybe there's a way to beat the machine. Maybe there's a point to all of it. Or maybe there's not. 
 This isn't quite as gripping or fast-paced as I remember it being, possibly because I've read an awful lot more psychological thrillers since being 10 years old, but the ideas are still pretty sharp. And it was still compelling. And, let's face it--it's stuck in my head well enough over these past 20 years that I can recite the final creepy line from memory, and that's not something you can do with a forgettable book.