Spirit's Eve is a festival in Pelican Town where the townspeople recognize the spirits within the town and prepare for the winter season. It's identical to the celebration "Halloween" in real life.
This festival begins at 10:00 pm on the 27th of Fall. Spirit's Eve ends when you exit town left, and will teleport you to your farm, at 12:00am.
The main attraction is a haunted maze set up around the community center. Many of the townspeople will be carving pumpkins or eating food at the buffet, but most are inside of the maze.
There is a shop set up which sells one of the Rarecrows (2 of 8) for 5000g, Jack-o-Lanterns for 750g as well as the recipe to make Jack-o-Lanterns for 2000g. Like any other planted crops, when placed down, Jack-O-Lantern will wither when winter arrives.
Unlike many other events, there are no contests or challenges apart from completing the maze.
The haunted maze is set up by Rasmodius. He is so committed to creating a frightening maze that it will take him all day to set it up. During this time, the player cannot enter the town square through the Easternmost exit of the farm. A large majority of the townspeople are either frightened or confused by the maze (especially Abigail, who won't continue due to her fear of spiders).
The town's children will not be allowed in the maze because their parents think it is "too scary" for children.
The trick to reaching the end is to take the secret passage, which begins just underneath and to the left of the "?" signpost, and then continues along inside the cave to the north, which requires a little blind navigation to the right (you can wear a "glow ring" to know your position), until you finally exit down into the treasure section of the maze.
A golden pumpkin is given as a reward for finishing the maze. Though it has no purpose in farming, it is worth 2500g.
Stardew Valley Fair • Spirit's Eve