Imagine a piece of exercise equipment that measures a couple thousand square feet in size, is available 24 hours a day, and comes complete with a comfortable couch and a refrigerator full of healthy snacks. If that sounds a lot like your home, it's because it is. By modifying the things you already do, you can turn your home into a fat-burning machine without eating up much of your increasingly rare spare time. And these techniques don't cost anything to implement. Here are six ways to get started.