Whether you want to stretch before you go to sleep or psych yourself up for a big day, try Yoga in Bed, a new fitness DVD ($20, www.amazon.com) that offers a quick (12- to 15-minute) routine of simple poses suitable for beginners. There’s no need for a yoga mat, just your bed and some pillows and blankets. You might not be able to work in your pj’s, but at least you can work out in them.