Considering OCS Amigas I think old DPaint and SoundTracker could be worth it. They are outdated but audience could try some old classic images and tracks just for memories.
Have some old classic demos and games running. There is plenty to choose from...
When it comes to AROS, AmigaOS 4 or MorphOS it is probably better let people tinker with those machines with whatever software they have there. Just give some instructions what software there is and how to try it out. People maybe don't know that OWB is a web browser and so on...