MainXchange Inc. is an internet stock market game. By downloading and playing this free market simulation, students can learn how the stock market works. The free software includes a personal portfolio, online “personal consultants” to help students pick stocks, and links to real-time business news from CNN so students can track trends and research companies. Students can even compete for prizes. If you don’t mind the commercial aspect of the game, it’s a useful tool for teaching high school students about the world of business and investing.