The cast of Woolly’s “Barack Stars”. Written by DCist contributor Monica Shores Woolly Mammoth shouldn’t have trouble selling tickets to its current show, Barack Stars; the reputation of Chicago’s Second City comedy group will do most of the work. The legendary improv school fostered the careers of entertainers like Stephen Colbert and Dan Castellaneta (the voice of Homer Simpson), and regularly supplies members for the cast of “Saturday Night Live,” from Tina Fey to…