Gym bags are an essential for anyone interested in staying fit. Whether you're into cardiovascular activity, weight training or even yoga, there's a bag for you. Most gym bags are simple, smaller one-compartment duffels that have just enough room for your workout clothes, shoes, a towel and your music player. Many also have smaller zippered accessory compartments for keys, wallets and other small items. Yoga-specific bags offer similar features, plus the added convenience of carry straps for your rolled-up mat.