The Mayor will stop by the farm on the day before the festival to ask the player to bring a food item to be thrown in the pot. At the festival, the Mayor will ask the player to throw something in the Pot (an Egg is a good choice). After throwing the item in the pot, everybody will eat. The villagers reaction to the Pot Luck is based of the item added by the player.
The player can get stuck on the top of the pot if they climb too far up the ladder.
If the player throws their dog into the pot, when they return to the square the next day, it will be stuck behind the hedge in the top corner. You won't be able to retrieve he/she but they will still be able to particpate in the dog festival every year though.
It is possible to use your fishing rod in the pot. It is also possible to get fish.