Sophie's World is a fun novel and a map of the historical development of philosophy.

http://en.wikipedia.org/wiki/Sophies_World

The first book on philosophy that both blew my hair back and made me realize philosophy is alot more than just academic was You Can Trust the Communists (to be Communists).

http://www.writing.upenn.edu/~afilreis/50s/schwarz-cover.htm...

My best friend in college was a Russian Jew whose family immigrated to US during the Cold War, and he kept that book on his coffee table.

It's the Yin to Howard Zinn's Yang - A People's History of the United States - which even though it's not philosophy is worth reading too.

http://en.wikipedia.org/wiki/A_Peoples_History_of_the_United...