There is a breed of computer simulations, known as "artificial worlds" or "would-be-worlds", that allows scientists to create artificial versions of real-life phenomena inside their computers. This work describes how far these simulations have come and how they are being used as problem solvers, predictors, and simulated scientific experiments. These "would-be-worlds" have already tackled many real-life problems. Urban planners have used one to study traffic flows. Meteorologists use simulations to predict blizzards with incredible accuracy. And scientists are even using these powerful models to study how the brain works.