The Minnesota Fringe Festival is the largest event of its kind in the US, but the fest’s new chief had her hands full this summer. Opening day coincided with the aftermath of the catastrophic collapse of an interstate highway bridge in Minneapolis, an event which mesmerized the nation (or at least the national media.) But the festival is plowing ahead, and sticking to a unique system of show selection under which even proven success stories from past years must subject themselves to a random drawing to determine who will get the chance to perform.