Longnight

An event around the winter solstice, longest night of the year. Also called Midwinter or Sharmeet, this day was sacred to the Dark Lady Shar, Mistress of the Night. In legend, Shar spent most of the year quarreling with her twin sister Selûne. As the goddess of the shadows, Shar's power grew as the days grew shorter, culminating in the longest night of the year. As her power overwhelmed Selûne's defenses, it was believed by many races that any who were out and about in the night, or any who spent the night alone, would emerge the next day as changed individuals.
To protect their clans from Shar's wrath, Orcs of the Plains would build large shelters in the days before for the whole clan to live in, only emerging after the night ended. Some clans lived in the large shelters for only the singular night of the solstice; others lived in them from the new moon prior to Longnight until the new moon after, although they left the structure during the day. The structures varied from elaborate, permanent settlements, returned to year after year, to mud-based daub lodges that were destroyed after the event.
The elves, and by extension the Druids, believed that Longnight was the night where Dark Lady Shar and Queen Lloth, a dark goddess of spiders, aligned, wreaking havoc on any who were not suitably protected. As such, most elves stayed indoors for the night, barring doors and windows with iron or rue, and spending the night in silence to avoid attracting the attention of the two dark goddesses.
Drow, although once elves, view Longnight as a time of celebration; as they are beings of darkness, Longnight is one of the few periods of time where they may move freely for most of the day. They celebrate Longnight with songs, music, and walks in the dark; however, they do still hold on to the old elven tradition of protection through iron or rue, and may carry talismans made out of one or both, and do not dare venture out alone.