What If?: Serious Scientific Answers to Absurd Hypothetical Questions
Randall Munroe is a very strange individual, probably in a good way.
What If is exactly what it says on the tin. It's peculiar, often funny, an easy read, and fairly lightweight. You might pick up some random science facts that you can trot out at parties--thus causing you, by the Law of Conservation of Epistemology, to forget things like the quadratic formula--although you won't really learn much of substance.
Still, there's a hidden value in What If: it gives a pretty good thumbnail sketch of how scientists (and engineers!) actually think. You may well get more out of the book if you read it less for the answers and more for the process of how those answers come about.