Since it's chilly outside, many of you have probably brought your workouts indoors. Hitting the gym, pool, or fitness classes are great forms of exercise, but let's face it — sometimes it's tough to muster up the energy to head out the door. That's when doing exercise DVDs at home comes in handy. There are thousands to choose from out there for every type of fitness from strength training, to dance, to yoga, to routines with hula hoops. If you've followed along with DVDs you own over and over again, you're probably bored of them. Instead of going out and buying a bunch of new DVDs, just like swapping your iPod with a friend, you can trade fitness DVDs. Lend a fellow active buddy your favorite Shiva Rea video, and she can let you borrow her Billy Banks Tae Bo series. Not only will you save money, but since your friend recommended it, you'll also know the video is actually good, so it'll also save you the frustration of buying a crappy fitness DVD.