In It's Not a Bed, It's a Time Machine, a clever picture book by Mickey Rapkin and Teresa Martinez, a young boy anxious for bedtime discovers his bed is a time machine Bedtime means lights out, with dark corners and spooky sounds. But it also means . . . Adventure Because it's not a bed, it's a time machine. Our hero rides it to the coolest time of all--the age of the dinosaurs. He makes a tyrannosaurus-sized...