Speculative Enactments are a novel approach to speculative design research with participants. They invite the empirical analysis of participants acting amidst speculative but consequential circumstances. HCI as a broadly pragmatic, experience-centered, and participant-focused field is well placed to innovate methods that invite first-hand interaction and experience with speculative design projects. We discuss three case studies of this approach in practice, based on our own work: Runner Spotters, Metadating and a Quantified Wedding. In distinguishing Speculative Enactments we offer not just practical guidelines, but a set of conceptual resources for researchers and practitioners to critique the different contributions that speculative approaches make to HCI discourse.