House of Stairs by William Sleater; several teenagers are kidnapped and locked in a white building full of seemingly endless stairs. There also seems to be no way out. It turns into a nice character study, true colors and all.
Fahrenheit 451 by Ray Bradbury; Imagine a world where firemen start fires...they don't put them out. Ray Bradbury is one of my favorite authors.
Something Wicked This Way Comes by Ray Bradbury; An evil carnival arrives at a small town....
Red Kayak by Priscilla Cummings; A prank results in a death; devastating, illuminating story.
Blue Skin of the Sea by Graham Salisbury; Short stories about a boy growing up in Hawaii.
Dr. Franklin's Island by Ann Halam; after crash-landing in the middle of the ocean, the only three survivors, three teenagers, find themselves stranded on an island. I think of this as an Island of Dr. Moreau retelling, but for teens.