This is the final week to see Eugene O’Neill’s 1922 experiment in expressionism, The Hairy Ape, at American Theatre Company (ATC). No, it’s not about a monkey in the zoo, although that’s where the final scene takes place. It’s O’Neill’s leftist-leaning look at the Great Unwashed industrial proletariat—represented by Yank, a coal stoker on a steam ship—and the human compulsion to find self-worth and ascend the social ladder. New ATC artistic director Damon Kiely offers an almost-choreographed production, and turns O’Neill’s words into music-like spoken riffs. (773) 929-1031; $25-$30; through May 18.