Ch’ang O’s themes are the moon, relationships, purity, devotion, instinct, growth and manifestation. Her symbols all lunar symbols or items. This Chinese moon Goddess is stunningly beautiful, shining on our lives with all the best energies of the moon. On this day, Her birthday, She reaches out to embrace the earth and its people, inspiring pure, devoted relationships, stirring long-forgotten insights and sharing energy for growth and manifestation in nearly any area of our lives.
Celebrating the Birthday of the Moon is in honor of the moon Goddess and is a national event in China; the traditions are easily adapted to our efforts. Begin by gathering with family or friends and exchanging moon gifts (anything that represents the moon and meets a magical need for the person to whom it’s intended). After the gift exchange, enjoy some moon-shaped cookies or cakes, as well as other foods that invoke Ch’ango’s favor, like dumplings shaped like a crescent moon (dim sum) and grapefruit slices.
Don’t forget to go moon gazing (if the weather is poor, use a poster or book image). Hold hands with your companions and bask in the silvery glow. Moonlight is said to enliven creativity, romance, and other positive emotions today.Additionally, looking upon Ch’ango’s visage draws the Goddess’s blessing and protection.”
(Patricia Telesco, “365 Goddess: a daily guide to the magic and inspiration of the goddess”.)
Patricia Monaghan writes: “In ancient China, it was said that this moon Goddess originally lived on earth, where Her husband was a famous archer. To honor the mans’s prowess, the gods gave him the drink of immortality, but Chang-O beat him to the bottle and drank it down. Then She fled to the moon, where Shed asked the hare who lived there for protection from Her (probably righteously) furious husband.
There, some say, Chang-O gained immortality – as a toad. Other legends say that Chang-O’s residence was one of the twelve moons, each a different shape, that cross the sky” (p. 84).
Now apparently, there are at least 3 different versions of Her story; click here to read them.
While researching Chang-O, I found this commentary particularly insightful: “I feel like She has grown beyond Her silly mistake – that perhaps that was the necessary fumble for Her, so She would be in isolation, and able to explore the mysteries of humanity and divinity in solitude.
I see Her, not as selfish or stupid, but as gentle, and grown wise from Her mistakes. I feel that She has a lot of compassion for humans, being that She once stood where we are now.” 
“Alternate names: Hêng Ô, Chang E, T’ai-yin Huang-chin (‘The Moon Queen’), Yuehfu Ch’ang Ô (‘Ch’ang Ô of the Lunar Palace’)”. 
Autumnsdaughter. Tarotforum.net, “Goddess Tarot: 9 ~ Contemplation: Chang O“.
Monaghan, Patricia. The New Book of Goddesses and Heroines, “Chang-O”.
Took, Thalia. A-Muse-ing Grace Gallery, “Ch’ang Ô“.
Kuchinsky, Charlotte. Yahoo! Voices, “The Myth of Chang O, Chinese Goddess of the Moon“.
Moonbird, Maeve. Order of the White Moon, “Ch’ang-O Chinese Goddess of the Moon“.
Wikipedia, “Mid-Autumn Festival“.