A popular activity around here is "historical reenacting", in which participants imaginatively recreate, through costume, custom, and behavior, their romanticized version of what life was like long ago. They gather at actual historic sites and go about their hobby to the delight of visitors who often pay admission to witness, photograph, and videotape the event. Its an interesting, though predictable, activity. History doesn't change.
Why not have a "future festival"? People could dress up and behave as if it were decades or centuries in the future. Participants could design and build prototype exhibits reflecting future technology regarding communication, transportation, medicine, housing and construction. They could wear the clothes of the future, eat the food of the future, talk the language of the future, all in a festival area made to look just like the future, with all of the things they imagine it will bring. The possibilities are limitless, and totally unpredictable.