Railroad Tycoon 3
You've all seen the mentos/coke videos. Imagine that explosion inside your car. That's what happened to me at lunch, soaking me and my new car is fizzy sticky stuff, after I opened my coke bottle. So I went home to change, and somehow started playing Railroad Tycoon 3. Lots of economics. You have to master bonds, the stock market, hostile takeovers, and of course the details of "consist" - hauling cargo. Fun game.