The Celestine Prophecy, by James Redfield is a thought provoking philosophy written in novel form, and though Christianity is in the story, the philosophy, for me, was fresh and not "Christian" in the mainstream.
It's a 4 book series, but so far, I've only read book #1
The book blurb:
In the rain forests of Peru, an ancient manuscript has been discovered. Within its pages are 9 key insights into life itself -- insights each human being is predicted to grasp sequentially; one insight, then another, as we move toward a completely spiritual culture on Earth.
Drawing on ancient wisdom, it tells you how to make connections among the events happening in your life right now and lets you see what is going to happen to you in the years to come. The story it tells is a gripping one of adventure and discovery, but it is also a guidebook that has the power to crystallize your perceptions of why you are where you are in life and to direct your steps with a new energy and optimism as you head into tomorrow.