After experiencing 20 years of success in Lincoln Park, Potbelly Sandwich Works opened a second location in the heart of the Loop in 1997 (although the address is on Madison St., the entrance is on Franklin). Patrons choose from one of nine classic submarine sandwiches, including turkey, Italian and the Wreck (4 types of meat), which are run through an oven and then customized with a variety of toppings. It hasn't take long for these inexpensive (if somewhat small), warm bundles of joy to win the loyalty of the Loop lunch crowd--a quickly moving line usually stretches out the door from 11 a.m. to 2 p.m. Seating is limited in the old-time dining room, which features antique decor and a hi-tech player piano--however, there are outdoor plazas and parks nearby for warm-weather picnicking. Ice cream, malts, milkshakes and frozen yogurt fruit smoothies are also available.