Want to have some fun for free? Play National Decision Systems' lifestyles game, which uses the Micro Vision consumer segmentation system to classify customers into one of 50 segments based on census demographics, interests, purchasing patterns, and financial behaviors. Users enter a ZIP code to discover the types of people who live in it. For example, more than 91 percent of people living in the 10016 ZIP code (home to the New York office of American Demographics) are classified as "Successful Singles," adults aged 25 to 54 with very high incomes who live alone. They're likely to meet others at their favorite hangouts like coffeehouses, live theater performances, and museums. And at the end of a long day they sip imported vodka and wine, watch ABC News Nightline or just curl up with the latest issue of Business Week. Don't expect to get a complete marketing plan from this freebie site, but it's definitely worth a look.