iO, or iO Chicago, (formerly known as "ImprovOlympic") is an improv theater and training center in central Chicago, with a former branch in Los Angeles called iO West and in Raleigh, North Carolina called iO South. The theater teaches and hosts performances of improvisational comedy. It was founded in 1981 by Del Close and Charna Halpern. The theater has many notable alumni, including Amy Poehler and Stephen Colbert.
