Former Northwestern classmates John Scheinfeld (The U.S. vs. John Lennon) and Rich Christian reunited to follow the Cubs through their tantalizingly promising 2008 season for the new documentary We Believe: Chicago and its Cubs, which premieres Friday at the Chicago Theatre.  The film follows current and former players, team officials and celebrity fans from Billy Corgan to Hugh Hefner, from the heady days of spring training through their ill-fated National League Division Series against the Dodgers.  As much as it is about the game, We Believe is about the unique character of Chicagoans who have remained loyal over 100 years of dashed hopes.  We Believe screens at 7 and 10:30 PM at the Chicago Theatre, 175 N. State St.  Tickets for the late show are available for $6-25.