With Thing One's interest in Percy Jackson, a study of ancient Greece seemed appropriate this fall. I put together a list of ideas for lessons, using several resources.
Usborne Book of Greek Myths
Story of the World Volume I, text and activity book
Kingfisher Book of the Ancient World
History Pockets Ancient Civilizations
Greek Mythology Activities
Some of my favorite ideas:
Use a compare/contrast chart to compare creation myths.
Go for a nature walk to look at the changing leaves, and talk about the story of Persephone.
Go for a spider hunt and talk about Arachne.
Read about Atlas, and discuss what an atlas is, find some at the library.
Plant narcissus bulbs and read the story of Narcissus.
Read about Daedalus and Icarus, and make candles.
Read about the chimera and make up your own mixed up animals.
Read about sirens and play with sound.
Read about Theseus and the minotaur, and go to a corn maze.
Learn about Greek architecture, and make a gingerbread parthenon.