I'm sure I would have loved this as a teen boy.  It's short, it's fairly quick to read, it's weird, and it has a strange ending.  Now, I'm not loving it, but it's not the book's fault or that of Mr. Vonnegut.  Why?  It came at the wrong time of my life, probably.  But more on that later.

In Cat's Cradle, our narrator, John (or Jonah; he sort of explains that's it's both), tells us the story of his trip Caribbean nation of San Lorenzo and his subsequent adoption of the local religion "Bokononism".  Or maybe it's not about that.  Maybe it's about John (or Jonah's) investigation of the life of one of the (fictional) fathers of the atomic bomb, Felix Hoenikker and his odd children.  Or it's not either of those things.  It could be about the madness of the arms race and the uses and absues of science.  Point being, a weird made-up religion that everyone believes anyway, a dying dictator, and a crazysuper weapon are all involved.  Whatever: it's probably about all these things, and likely some other stuff that I haven't noticed.  

Cat's Cradle is filled with lots of pop philosophy that is great for young minds. This is the kind of book the "cool" English teacher would give his students, the one that opens their minds and gets them thinking.  It feels a bit rebellious, and is a frequent target of banning.  The fairly simple writing and the light humour cover a deeper message, and makes for a thought-provoking story.

As an aside, while I never read this one when I was a teen, I read a couple of others that performed the same role for me: Time Enough for Love by Robert Heinlein and Jostein Gaarder`s Sophie`s World.  Both explored philosophical ideas from various perspectives, both got weird in the end and both kept me up all night, just thinking about stuff.  I`m sure if I went back I`d find them a bit less appealing, but I loved them at the time.  Are there any books that affected you the same way?