A mind forever voyaging is one of Infocoms all time classic games. Set shortly in the future, you take the role of a sentient computer, developed to take part in a simulation of the city you are based in, to see how policy changes will effect the city in the future. Very dark, and has some of the best story writting I've ever seen in Interactive Fiction. Very hard, and not one you will finish quickly. It's essentially two genre's of game, where you are just the computer, and where you are logged into simulation mode.