Conversational interactions have revolutionized how we interact with technology. Given that large language models as conversational user interfaces (CUI), e.g., ChatGPT, are now commonplace, the significance of exploring creative designs of CUIs cannot be overstated. This course within our ID master's program explores the ongoing CUI research, design strategies, and development methodologies behind designing effective CUIs. Through invited lecturers and active prototyping, we delve into the core concepts in human-computer interaction (HCI), design, and improvisational theater to equip students with the knowledge and skills necessary to create compelling conversational experiences.