Libraries, as authoritative custodians and providers of information, are facing a number of challenges as they are trying to adjust to the new information environment. Some challenges arise from major paradigm shifts in recent decades relating to the understanding of the nature of information processes and conceptions of authority. Engagement through serious play is proposed as a way of dealing with discrepancies between traditional roles and contemporary demands, enabling experimentation and exploration of future roles. Two organisational projects from the University of Technology, Sydney Library are used as examples to demonstrate how playful engagement can be applied to planning for the library of the future. Insights from the two projects and literature point towards serious play as a promising approach to library innovation and change.