Gamearth

This book is one of those few that really captures the imagination, and one of my favorites from the age of 14 through college. There are two ongoing scenes, one with the "real world" people playing a medieval role-playing-game, and the other focuses on what goes on with their characters in Gamearth... When one of the real-life gameplayers decides to destroy Gamearth, the characters have to act independently to escape the game-world and come into the real one, proving that their land is alive and more than just figments of the players' imaginations. You get to see both the side of the real-world reacting to the characters refusing to do what they are told AND the characters' points of view as a roll of the die brings chaos to their land. Perfect for anyone trying to write stories or playing RPGs, as it brings into question the idea that our "imaginary" world might be more than something we just dream up that goes away when we close the book or stop the game!