Calling all drama queens. This is a play, so the genre is kind of a gimme: it's drama. And the good thing is, you don't even have to cry or have your feelings hurt; there is plenty of action in Inherit the Wind that provides all the juicy excitement you'll need.
Plus, since the play is based on a real historical event (the Scopes Trial of 1925), but retells the events using fictional characters, it can also be called Historical Fiction or Historical Drama. And you thought reenactments were only for the Civil War.