The Faerie Festival is on Sept 20th. It's a special day dedicated to Neopia's faeries. It is hosted by a different Faerie every year (whether Dark or Good). You can complete a Faerie Quest once per day of the festival.
In Y12, all Faeries at the Faerie Festival were turned to stone by a mysterious spell. This petrification became the foundation for the plot "The Faeries' Ruin". As a consequence, in Y13, Y14, Y15, Y16, Y17, and Y18, the Faerie Festival was abruptly cancelled due to someone has vandalizing the area.
In Y19, it came back with a Winter Starlight-esque feel to it, with the Wheel of Excitement, Soup Kitchen, Wing It, and Free the Faeries. There was also a bonus prize awarded for visiting each day until the 26th, but some users who have visited each day were not being awarded it. It was canceled on the 27th due to some Wraiths vandalizing the area.