Musical! The Musical, Players Workshop, at the Chicago Center for the Performing Arts. It wasn't that long ago that a troupe able to improvise for 20 minutes based on a single audience suggestion was considered a prodigy. These days everyone does that, though not always well. Those who want to stand out have to raise the bar, like the Players Workshop folks, who improvise a two-act musical.
Of course just because you've raised the bar doesn't mean you can reach it. Several years ago this troupe wowed me with their improvised musical version of The Exorcist. But their ad-libbed musical take on To Kill a Mockingbird here--in a different venue but with most of the same ensemble members--was not so impressive. It might just have been the luck of the draw--the performers choose quickly from movie and book titles the audience blurts out--but this show was more bland than funny. Maybe the 1960 Pulitzer-winning novel and 1962 movie based on it are cows too sacred to gore. Or maybe the lily-white ensemble didn't feel up to tackling race relations or, God forbid, imitating Harper Lee's African-American characters.
More likely, however, the show suffered from the usual improv malady: underinformed, ill-prepared performers. These five knew enough about the story to more or less re-create it (sans minorities), right down to Sara Wolfson's very funny take on protagonist Scout. But they didn't know enough to say anything about it.