Some kind of software controlled drone/robot should do it, since there are 2 parts, software and hardware.
Perhaps using a Raspberry Pi and leveraging CV / NLP off the shelf tools.
Even easier-- go to adafruit and get a circuit playground. Lots of shiny lights LED patterns, easy to program.
Also, perhaps check if their are any makers, robot groups, model rocket groups, drones (look for a meetup) in your area. There may be someone around you. You might find someone with an interesting project to bring to the event.