It's hard to stay fit when you're putting in long days building a business. That's exactly why the Web may be your best fitness coach ever-whenever you're at your desk, there are fitness sites waiting for you to click in and start shaping up. A prime starting place: MyFitnessClub, which provides personalized information and tools to help you maximize your workout. The site offers plenty of encouragement and tips. Members pay $5 per month, but joining gives you free benefits (like discount coupons good at online retailers or a free, $50-value assessment of your wellness).