This paper explores the nature and potential of improvisation as a method for learning and teaching in CSCW and HCI. It starts by reviewing concepts of improvisational learning in classic and more recent work in educational theory, art and music, and HCI that emphasize the reconstructive, materially-driven, error-engaged, transgressive, and collaborative nature of human learning processes. It then describes three pedagogical interventions of our own in which improvisational techniques were deployed as methods of teaching and learning. From this integrated study, we report specific pedagogical conditions (socio-material evaluations, multi-sensory practices, and making safe spaces for error) that can support improvisational learning, and three common challenges of HCI pedagogy relevance, assessment, and inclusion that improvisational methods can help to address.