While the Hellenistic rituals are pretty fun, and children are easily included--washing their hands and face, throwing barley grains, acting as carriers of water, wine or offerings, etc.--there are most certainly specifically Hellenistic activities that you can undertake with your children to make the day memorable and prepare them for the rituals, should you so desire.
- let the children design their own Hellenic clothing, and have a fashion show to show off the designs
- pick flowers with the children and let them make their own wreath to wear for the festival
- assist the kids in writing a mythologically inspired play, and let them perform it on the day of the festival; this play can be inspired by existing plays, of course
- play '20 questions' with the kids by having them stick a post-it with the name of a Theos or Theia on it on their foreheads and asking each other questions to find out who they are
- make temples of their own design with the kids; these can be drawn, fashioned out of clay, made out (or inside of) shoe-boxes, or with bricks and wood, if you have the resources at your disposal
- a similar assignment can be done for altars, pottery, columns, statues, or ancient Hellenic houses
- Hellenic shields and helmets can be made out of cardboard
- how about drawing monsters on cardboard and cutting them out? They can play 'Hēraklēs' with them afterwards and vanquish them
- collect as many rocks and other markers as you can find and lay out the lines of a temple behind the altar, so they can play at being priests and priestesses
- alternatively, the kids can make a labyrinth and find the heart of it, like Theseus when he went to hunt for the Minotaur. Having them find their way out is also an option, of course
- cook as much Hellenic food together as you can stomach and have a tasting party
- let the kids read and study the Hellenic alphabet, and compose coded messages to each other. Use clay or plaster to create a plaque the students can carve their name into. Use a paperclip as a hanger (apply to the plaster or clay while it hardens) so the plaque can go on the wall. Stone fleck paint or simple gray paint can be used to 'stonify' the plaque afterwards.
- make ancient Hellenic coins out of clay, carving images into it, or using the clay to make a mould that you can pour tin in. Note, tin fumes are poisonous and is has to be melted! Don't let the kids do this themselves!
- host Olympics with kids-appropriate sports like long jump, sprints, relay races, and things like frisbee throw, space hopper races, and rope jumping competitions
As you can see, there are a thousand-and-one things to do with children that will teach them about ancient Hellas, and make a festival day extra special. Besides, most of these things, I would love to do myself; the space hopper races, especially!
Image taken from: Culture24