Formerly called ImprovOlympic, I.O. is the city's home for long-form improvisation. The signature piece is "The Harold," in which a team of improvisers explores a single audience suggestion throughout a series of stories and characters until they all eventually weave back together to fit with the original audience idea. There's no drink or age minimum. Seating is first-come, first-served, so be sure to arrive early, especially for weekend shows.