Cryptonomicon - what a beast! This is a novel that's hard to actually describe but a joy to read.

At its simplest, it's about WWII cryptographers and present-day hacker types hunting for gold in the Philippines...Neal Stephenson collides inventive cyberpunkish fiction with historical characters (such as Alan Turing), plus the occasional detailed technical explanation of how things work (say, a pipe organ, or the male libido). And even though Stephenson is clearly many times smarter than me, his writing is charming, informal, and generally hilarious.