I have been meaning to post this for quite some time now. Three books I read recently (well, more like 5 months ago), all of which have something in common - they might just change the way you think about the universe.
A Short History of Nearly Everything by Bill Bryson. Just about everything in this book has been done before but it's still quite something to see so many diverse branches of science presented in a compact, accessible format like that. And the descriptions of truly ancient forms of life that can still be found in remote areas of Australia today is really fascinating.
The Curious Incident of the Dog in the Night-Time by Mark Haddon. A great idea well executed, and many people elsewhere on the web have written much about this book so I won't go into great length about it. But there is one part in particular which really made me think - the part about how the mind and consciousness works. This was really fascinating to me since in my opinion the mystery of consciousness is one of the great mysteries of the universe but the hero of this book says (effectively) "oh, this is how it works" and describes a very coherent theory in a very matter of fact way.
One of Us by Michael Marshall Smith. Smith is a British novelist who writes brilliant science fiction novels which are incredibly imaginative and superbly paced but also very very gory, gratuitously violent and disturbing. Actually "One of Us" is probably less gory and violent than the other two novels of his that I have read ("Only Forward" and "Spares") but still only recommended for the non-squeamish people. To say how this book explains the mysteries of the universe would be to give away the ending so I won't say any more about it here.