Stuart Frankel is a Subway restaurant franchisee in Miami, Florida. After noticing sagging sales on the weekends, Frankel came up with an idea–he would sell footlong subs for $5.00 on Saturdays and Sundays. His sales immediately soared by double digits and to Frankel’s surprise, his profit margins didn’t decline. Other stores tried the idea and also experienced great success. At first skeptical, Subway’s headquarters eventually adopted the idea and launched a nationwide campaign on March 23, 2008. The results were astounding with sales of $3.8 billion by the the $5 footlong alone. That catapulted Subway into the top 10 fast-food brands in the U.S. In fact, in the last five years, Subway has opened more than 9,500 stores–an average of more than 5 stores every day. It currently has over 32,000 outlets and early next year is expected to surpass McDonalds in it’s number of locations worldwide. You can read the full BusinessWeek article right here.