This article argues in favour of seeing co-design as an open-ended exploration where prototypical practices are explored that engender favourable conditions for ongoing negotiation of meaning. Participatory design approaches to designing for specific practices are reviewed with particular focus on how to handle constantly evolving practices, where some design researchers argue for creating open and flexible technical systems while others emphasise design as primarily concerned with questions of changing practices. By discussing an extended participatory design project in which new ways of engaging in informal learning through self-produced videos were explored in an intensive care unit, I argue first and foremost for viewing co-design as prototypical practice which is explored through an open-ended exploration of possibilities. Second, I argue that a focus on practice necessarily requires in situ explorations to see if the proposed design explorations invoke relevant prototypical practices in the midst of work. Third, I argue that a focus on practice entails viewing tools as temporary props for various settings, rather than as central features that define the settings of learning, knowing and working.