Based on the journals of August Strindberg, one-man show Inferno Sonata visits the Swedish playwright late in his career, separated from his wife Frida, and descending into madness as he attempts to discover the secret of alchemy. The terrific Scott Sharplin, who also wrote the script, pitches his performance at just the right level of over-the-top, imagining Strindberg as a kind of cackling Batman villain (apparently not that far from the truth), seething with professional jealousy towards Ibsen, and teetering on the brink of 10,000 different nervous breakdowns. With some charmingly gonzo stage decoration and props, this is an idiosyncratic gem.