Improvised acting is a viable technique to study human communication and to shed light into actors' creativity. The USC CreativeIT database provides a novel bridge between the study of theatrical improvisation and human expressive behavior in dyadic interaction. The theoretical design of the database is based on the well-established improvisation technique of Active Analysis in order to provide naturally induced affective, goal-driven interaction. The carefully engineered data collection and annotation processes provide a gateway to quantify and investigate various aspects of theatrical performance and human communication.