Reamde: A Novel
Enjoyable. Long. Somewhat derivative of some other works that explore the relationship between the real world and a game / virtual world, e.g. Lev Grossman's Codex. If you liked Cryptonomicon, I think you'll enjoy this, although to my mind Cryptonomicon is better. I found this much more accessible that Stephenson's other recent works, in particular the Baroque cycle, which I found more or less impenetrable.