Neal Stephenson has a fairly insane imagination.
Snow Crash is the story of a guy named Hiro and a girl named Y.T., both of who live in a near future L.A. where society has broken up into innumerable franchises where most people live out their lives in predictable sameness.
However, for those who are able to access it, there's also the Metaverse, where people wander a virtual world of infinite vareity. But there's a new virus that's striking people in the Metaverse, and Hiro and Y.T. end up in the middle of the fight to stop this virus.
The story brings together ancient Sumerian myth and modern technology into a dizzying story that finally makes sense in the end. I didn't find this book quite as dense as The Diamond Age (the other Stephenson book I've read), but it's definitely heading in that direction. The author is a master in interweaving a number of complex stories of seemingly unrelated people into something that manages to be surprisingly whole at the end. (That being said, he did a few back and forth forays in time in this book that were a little disconcerting.) He's a great author, but certainly not someone you'd want to read in a hurry.