This 24 hours is about exploring the future with scenarios, which are pictures of possible futures. Rob Hopkins' 'The Transition Companion' summarises a whole lot of them on pages 42 and 43. But for an in depth exploration of just a few scenarios - four - get hold of David Holmgren's 'Future Scenarios'. The four provide a great range: from urban high-rise to rural resettlement; from female-dominated to male-dominated; from super-rationalism to earth spirituality. There's a good summary on page 89.
Once you have a sense of what the four scenarios are about, you can play with them. You can do this with others by yourself. You can do this by visualising how places you know would change under of the scenarios. Or by imagining how some of our basic activities - feeding ourselves, working, playing - would change under each scenario. Or you could go for a walk and try to work out how the places and activities you see could vary.