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).
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 lack of organization.