Might I cheat and suggest the "Percy Jackson and the Olympians" series? If note, then I suppose I would say to start at the beginning with Lightning Thief. These books are deliciously clever not only in the voice of the narrator but also in their adaptation of classical mythology to a new setting. Although some of the fun comes from recognizing how the old myths get reinterpreted, so if you have no knowledge of Greek stories then it might not be as enjoyable.
For nonfiction, I would ultimately recommend Outliers: The Story of Success. While this book isn't particularly paradigm shifting, it has numerous small arguments that will hopefully lead to a larger scale perspective shift. Perhaps of greatest interest is that intelligence is not in itself a good indicator of actual success.
But if I could recommend two nonfiction books, the second would be The Printing Press as an Agent of Change. Its implications for the computer and the internet are most heartening.
