Cryptonomicon

First of all, I wouldn't recommend this to the average person. It's a very long read (I'm only half-way through it), and it has a lot to do with Alan Turing and the revolutionary work he was doing with the Enigma machine during WWII. It also has about 4 subplots which, as far as I have gotten, haven't really crossed paths completely yet. The jumping around between the plots made me lose some interest, but I have a feeling this complexity will be rewarding in the end. It's also a very long read. But, if you're interested in the subject matter, the first few pages will hook you.