Conversational User Interfaces (CUIs), from online chatbots to smart speakers, are increasingly being used to support children and family activities. This virtual workshop seeks to bring together researchers from academia and practitioners from industry who are interested in the design, development, application, and study of CUIs with a focus on children and family based interactions. We aim to examine the challenges involved in designing and developing CUIs that are capable of supporting everyday activities of children and families. Furthermore, we will also discuss the insights CSCW research can provide into understanding how CUIs can participate in collaborative activities of children and families. By bringing together existing researchers and new ideas in this space, we intend to map new areas of work including addressing the technical, social, and ethical challenges that lay ahead. Additionally, this workshop seeks to foster a strong community and enable potential future collaborations on this important topic.