Gary Griffin has become Chicago’s master concept director for musicals, scoring notable successes at the Chicago Shakespeare, Court and Marriott theatres and in London. He’s developing a musical for Broadway, too, based on The Color Purple. But currently, he’s back at the Marriott with an ambitious production of the legendary musical tragi-comedy, Show Boat, a huge undertaking. The score boasts ‘Old Man River,’ ‘Make Believe,’ ‘Can’t Help Lovin’ That Man of Mine’ and ‘Bill’ among other glorious Jerome Kern tunes. Show Boat runs through Nov. 30. (847) 634-0200.