In the wake of Hurricane Katrina, an entrepreneurial spirit rose that has given new meaning to the city of New Orleans and taken its businesses onto global success. One such success story is the Idea Village, a startup that organizes workshops and competitions involving M.B.A. students from the nation's top business schools. "Katrina did two things," says Tim Williamson, the C.E.O. of Idea Village, which recently sponsored New Orleans Entrepreneurship Week. "Everyone became an entrepreneur because everyone was starting over in some way—we became a startup city."  Second, he says, "our networks scaled globally."