Sophie's World: A Novel About the History of Philosophy. Tasty!
An intriguing book on several levels, though not light reading. Sophie's story surrounds a course in philosophy from the early Greeks to modern times; the author does an excellent job putting the essence (or highlights?) of complicated topics into stories and examples that are approachable. After all, Sophie (the recipient of this course) is only 15. Along the way, the story itself becomes rather philosophical, as the nature of the characters themselves and their reality is called into question.
Definitely worth reading if you've had any interest in philosophy but had difficulty getting into some of the concepts. After reading Sophie's World, I finally understand those references to Plato's "world of forms". And I prefer Sartre (though Berkeley sounded interesting too).