The Autumnal Equinox, the second of the Harvest Festivals, is the Pagan rite of Thanksgiving, also known as "Harvest Home." It's a Sabbat of celebration for the abundance of the harvest; a time meant for us to give thanks through song, dance, and feasts.
This is a time of balance, when day and night are equal once again. There may be a hint of sadness within us now, an inner sense of fear and trepidation, as the world begins to tilt toward the time of darkness. And so this Sabbat is also a time of meditation and introspection; a time to slow down the pace of our lives and to relax and recognize our own personal harvests during the year that is fast declining. It's also a time to appreciate the connection we have with those around us, as well as those who have gone before us. While the name "Harvest Home" is often ascribed to the fact that the crops are being gathered, it also references the sense of "community" that this harvest festival fosters, for it's through our kinship with those close to us that we endure through the long, dark, cold nights of winter.
Mabon is a Welsh name meaning "great son," and refers to the Son of the Great Mother, The Divine Son of Light. Mythologically this festival celebrates the story of Modron, the Great Goddess of the Earth, and the birth of her son, Mabon. According to the mythology, Mabon disappears (or is kidnapped) three days after his birth (thus, the light goes into hiding). Mabon is veiled in mystery in the womb of the earth, here personified as his mother, the Great Protector and Guardian of the Otherworld. Though his whereabouts are a mystery, it is only here that he can once again renew his strength and gain new wisdom in order to be reborn to the Goddess as the Son of Light. This is accomplished at Yule (Winter Solstice), with the aid of the ancient and wise animals: Stag, Raven, Owl, Eagle and Salmon. One can readily see the connection of this myth to the natural events occuring during this time. It also speaks to us of the Wiccan Mysteries of Life, Death, and Rebirth, and the sacrificial nature of the God.
This season also brings to mind the mythology of Persephone and Demeter. Some groups choose to celebrate the Sabbat by enacting this story in their Sabbat Circles, emphasizing the Mystery contained within the cyclical faces of the ever-constant Goddess.
Other cultures also identified this season with their own mythologies. In ancient Rome, it was a celebration to Mercury or Apollo. Christian Britain replaced the Welsh Mabon with St Michael, to whom churches on many sacred Pagan sites were erected. The Autumnal Equinox became known as the Christian Feast of Michaelmas.
Beyond Michaelmas, Mabon, and Harvest Home, the Sabbat has also been known as the Festival of Dionysus, the Wine Harvest, Harvest of First Fruits, Cornucopia, the Feast of Avalon, Equinozio di Autunno (Strega), and Alban Elfed (Caledonii, or Druidic - which celebrates the Lord of the Mysteries). The Teutonic name for this season is Winter Finding, which begins on the Equinox itself and continues until Winter Night, October 15th, which is the Norse New Year.
Symbols of this Sabbat include grapes and vines, wine, garland, pine cones, acorns, dried leaves, Indian corn, gourds, wheat, rattles (especially those made of gourds), and horns of plenty.
Since Mabon is a celebration of fruits and wine, traditional Pagan activities include fermenting grapes. Apples and vine products are sacred at this season, so apple pie, as well as other apple foods, are common at Sabbat Feasts.
It's also traditional to wander wild places and forests, gathering seed pods, nuts, and dried plants, both for decoration and for possible future magick.