B'n -- cold rice noodles tossed with grilled meats and vegetables -- is the perfect summertime meal. Head to your nearest Vietnamese restaurant, plop down four to six bucks, and they'll bring you a huge soup bowl filled with tiny rice noodles covered with your choice of grilled meats, shredded mint, julienned pickled carrots, and roasted peanuts. Mix up the noodles and you'll find bean sprouts, lettuce, and cucumber underneath. Pour over the accompanying bowl of nuoc cham, a clear, sweet-tart sauce made with fish sauce, and you've got an addictive, deceptively simple meal in a bowl. It's incredibly low on fat and brightly flavored, especially if you add a dollop of hot sauce. Many restaurants offer a vegetarian version that substitutes a soy-based sauce for the nuoc cham.