- 1984, Fahrenheit 451, Brave New World - All three of these books tackle similar themes and I think there's some benefit in reading them together. Each one gave predictions about a bad future, but they diverged in how they thought we'd get there. Probably the best book to follow these up with is 'Anthem'.
- To Kill a Mockingbird - To teach them that you must try to have compassion and put yourself in the other person's shoes. Also to show them how awfully unfair it is to judge people by color. (Yes, they'll get this in school too.)
- Various Heinlein - Oh, I'm sure they'll get heavy doses of the great man, but especially 'Starship Troopers' and 'The Moon is a Harsh Mistress'. I'll leave 'Stranger in a Strange Land' up to them, but I'll be ready to discuss it with them if they'd like.
- Sailing Alone Around the World - I very much wish I'd read this when I was younger. The story is entrancing and so is the idea of finding grand adventure. If they're interested, I'll follow up with 'A Voyage for Madmen'.
- Historical Fiction - Especially historical fiction set in United States. I'm thinking about some of the great stories like 'Gone With the Wind' but I'd be flexible. There is no better way to immerse a reader into a different world than with good fiction. In theory, you could teach all of American history this way but I'm not sure what that list would look like.
- Meditations, Analects, Proverbs - There is great benefit in dealing with bite sized philosophy. Sometimes it comes out trite, but some well grounded bits of wisdom will always come in handy.
- Poetics - The book from Aristotle. There may be no better way to understand how stories are told than through the words of the Scholar.
If you have suggestions, leave them in the comments.