Several months in, the financial crisis remains an immensely confusing phenomenon, linking everyday mortgage-paying Americans to boutique derivatives trading houses to Scandinavian pensions. While the particular cause of the crisis, its implications, and the best means of dealing with it remain a topic of vigorous debate, it has been unquestionably linked to the profligate tendency of Americans to live far beyond our means. I.O.U.S.A., which premiered at Sundance in January and saw theatrical release in late August as the full scale of the crisis began to dawn on Wall Street, looks at the problem of personal debt in the United States in much the same way Al Gore’s An Inconvenient Truth examines the climate crisis. The Chicago Cultural Center hosts a free screening Saturday at 2 PM with special guest David Walker, the former U.S. comptroller general who’s featured in the film.