Day of Shameless Gluttony
The Day of Shameless Gluttony is a ritual associated with the Autumnal Equinox. In the middle of the harvest season, many Altairians choose to take advantage of the sudden surplus of fresh fruits, grains, and game. While many Equinox traditions are about giving thanks, the Day of Shameless Gluttony is all about unapologetically gorging oneself on all the food that makes the Equinox special.
History
The Day of Shameless Gluttony dates back to at least 950 G. E. It perhaps got its name from faeries poking fun at moralistic human missionaries, who condemned the feasts as gluttony and waste.
It has remained pretty much the same throughout the years, taking place primarily in rural areas such as the Nursery Rhyme District. It is a well-beloved and anticipated tradition that comes back year after year.
Execution
On the day of the Autumnal Equinox, a huge feast is prepared. Through a Stone Soup Ritual, the table, located outside underneath the fiery-leaved trees, is prepared. This feast includes many dishes associated with autumn, making good use of native fruits, grains, and wild game, amongst other things.
It is at the hour of sunset when the feasting begins. These affairs are not civilized; it is custom to eat until you physically cannot anymore, not bothering with decorum or even utensils. The residents of the Nursery Rhyme District act just as the animals they are, attacking their food. Amberjack Cider commonly makes an appearance to help with this.
The feast ends when everything is eaten, which is usually some hours into the night. Most will fall asleep at the table, overcome by a food coma and possibly drunkenness. There they will spend the night until morning, when they will assist with cleaning up. Many will not eat again for days after the event, their appetites satisfied for the time being.
Human Perception
As mentioned above, human missionaries did not have a high view of the Day of Shameless Gluttony. In their eyes, it was yet another example of the faeries' sinful depravity. Conversely, the faeries of the Nursery Rhyme District saw the humans' refusal to indulge as suspect, perhaps linked to the perception of the humans' religion as evil, one that venerated death and decay over life and vitality. This was one of the many things that strained relations between humans and faeries in the olden days.

My favorite kind of tradition
You said it! That and the Thanksgiving Day Parade.