The folk belief of both festivals was and is that at a particular time of year the spirits of the dead mingle with the living. The old Celts made food offerings to the ghosts and lit bonfires to guide their way. Hungry ghost festivals of Asia also feature offerings of food, candles and incense, as well as entertainment for the ghosts -- music, plays, opera.
The tradition of hungry ghosts goes back to the time of the Buddha and is recorded in the Ullambana Sutra. In this sutra, the Buddha told a disciple how to save his mother from the Hungry Ghost Realm.
In Buddhist myth, greed and jealousy lead to a rebirth as a hungry ghost. Hungry ghosts have huge, empty stomachs, but their mouths are too small and their necks too thin to take in food. Sometimes they breath fire; sometimes what food they do eat turns to ash in their mouths. They are doomed to live with incessant craving. Hungry ghosts represent all of our greed and thirst and clinging, which bind us to our sorrows and disappointments.
For this morning's ceremony, an altar was covered with flowers and food -- mostly cookies and fruit -- in the back of the zendo. The hungry ghost altar was separate from the main Buddha altar, because hungry ghosts are afraid to approach the Buddha. Sangha members also brought canned and packaged food to be taken to the local food bank.
The morning's liturgy included chanting of the Sho Sai Myo Kichijo Dharani and the Kanromon, the Gate of Sweet Nectar Service to Relieve Suffering. Here is just a part:
Raising the Bodhi Mind, the supreme meal is
Offered to all the hungry spirits in the ten directions
Throughout space and time,
Extending outwardly and inwardly,
Filling the smallest particle to the largest space.
All you hungry spirits in the ten directions,
Please come and gather here.
Sharing your distress, I wish to offer you this food
And hope it resolves your thirsts and hungers.