This practice-based research project investigates a new approach to speculative design that is based on discussion-based events and participatory activities. Works of speculative design are frequently justified on the basis that they support a public discussion around controversial techno-scientific issues – an idea known as ‘design for debate’. Some commentators have suggested that events and workshops could be an effective means for supporting sustained engagement and dialogue – offering an alternative to the standard speculative design approach of presenting fictional scenarios as objects, images or films. This research project explores the potential of events as a medium for speculative design through the creation of two practical projects, both of which present a speculative proposal relating to science and technology. The first, ‘Science Holiday’, explores the idea of halting all scientific research for a period of one year; the second, ‘A 100-Mile Conversation’, puts for- ward a proposal for a suicide-themed walk through the English countryside. Both projects were presented in non-gallery spaces and were designed to facilitate discussion and encourage audiences to imagine futuristic scenarios. Analysis of the two projects, which draws on literature from participatory and dialogical art and from accounts of scientific institutions that have sought to run debates with public groups, identifies a number of issues and challenges that speculative design faces when it moves away from gallery-based displays and towards events and activities held in other public spaces. These include questions regarding authorship, documentation and display, and the need for greater awareness among designers of the motives behind many initiatives that seek to engage public groups with scientific topics. In conclusion, the project makes claims for the potential benefits of an event-based approach to speculative design, but argues that the strong emphasis on ‘design for debate’ is insufficient - and possibly even misleading - when seeking to assess the value of the field.