When you walk into a yoga studio, chances are you'll see big stack of woven blankets. These guys are wonderful to sit on at the start of class to get your back in comfortable, seated alignment. One of my favorite ways to use a blanket is in Pigeon. For a little extra help, I love rolling a blanket up and threading it under my bent leg for support. They're also awesome for Savasana: roll up a blanket and place it under your knees, or cover your body if it feels chilly in the room. Even if a teacher doesn't request it, if they're available, it's a great idea to grab one. You never know when they'll come in handy.