I always have copies of George Orwell's "Animal Farm" to give out. As I get older, I love seeing younger people flip out when they read it and see how applicable it is in modern life.
My taste for Orwell's two most read, Animal Farm and 1984 was especially dulled after I read his non-fiction masterpiece Homage To Catalonia which is a harrowing lesson in realpolitik and the socialist infighting of the 1930's.
Homage To Catalonia is a wonderful book. I would also highly recommend checking out Down and Out in Paris and London and Burmese Days (two works of fiction loosely based on events from his real life experiences).