[nitrogen]

I'm reading that book right now, and so far it's good. One can also read: Anathem, Snow Crash, http://qntm.org/ra, or (extremely NSFW) The Metamorphosis of Prime Intellect.

All of them explore the nature of reality and consciousness in some way.

To the parent commenter, please write your story. The world always needs good fiction.

[mhink]

The Metamorphosis of Prime Intellect is one of my favorite sci-fi novellas. But yes, extremely unsuitable for anyone with a weak stomach.

[kale]

Yahtzee (of Zero Punctuation) wrote a novel that used simulation as a plot device. It's called "Mogworld". I thought it was well done.