Heng O was the Chinese goddess of the moon. In Taoist thought about yin and yang, Heng O is the symbol of yin - cold, dark, and female. Here's one version of a story about Heng O (the whole story may have been learned from the Hindu story of Chandra):
Heng O was married to the heavenly archer Shen Yi. Shen Yi was never going to die because he had a magic drink of immortality. Heng O wanted to live forever, like her husband, so she tried to steal the magic drink from Shen Yi. She took the potion and ran away with it, drinking as quickly as she could. But Shen Yi still chased Heng O down and caught her before she could drink all of the magic drink. She had not drunk all of the magic drink, so she could not go all the way up to heaven with the other gods. But she had drunk enough of it to get to the moon. So there she sits forever on the moon.
Starting as long ago as the Shang Dynasty, about 2000 BC, people mostly worshipped Heng O at the Autumn Festival or Moon Festival, which falls around the time of the fall equinox. Like Thanksgiving, the Autumn Festival was a celebration of the harvest. As with Yom Kippur, about the same time of year, you were supposed to pay off all your debts and settle your arguments before the festival. People ate special moon cakes, a kind of fruitcake made of seeds, almonds, minced meat, bean paste, orange peels and lard. Everybody tries to visit their families, forming a whole family like the whole full moon.
To find out more about Chinese gods, check out these books from Amazon.com or from your library:
The Gods and Goddesses of Ancient China, by Leonard Everett Fisher (2003). For kids. One page for each god, with lots of pictures and some historical context.
Five Heavenly Emperors: Chinese Myths of Creation, by Song Nan Zhang (1994). Stories for kids.
Chinese Mythology A to Z, by Jeremy Roberts (2004).
Dragons and Demons : Myths of China, by Stewart Ross (1998). A few Chinese stories, retold for kids.
Dragons, Gods and Spirits from Chinese Mythology, by Tao Sanders (1983). More of a child's encyclopedia.