I take a 5 frame medium nuc with fames of foundationless with guide, foundationless with wax strip guide, wired frame, frame with foundation and a frame of drawn comb. Makes great show and tell and generates a lot of questions. Go to the Bee Culture Magazine site and download the free handout on the difference between bees and wasps, hornets, etc, for something to take home. I also take my smoker, veil, and hive tool, and wear my bee outfit while conducting the class. Explain the different ways of separating honey from it comb (extractor, crush & strain) and the advantages of both methods.
A good question to ask them is, "How many products in your house has honey or wax in them?' With older kids this can last for 45 minutes all by itself.
I have a miniture skep I made myself to show the "old way" of doing things. I posted directions for making it in the Crafting Forum.