There are several random events that can occur while the player sleeps. Listed below are all known random events that are not covered elsewhere.
There is a random chance that a meteor can fall from the sky onto The Farm at random tiles during night. A unique sound effect will be heard before daily earnings. In the morning, a message will pop up saying "An explosion was heard in the night..."
The Crop Fairy
During random nights of the growing seasons, there is a chance for the Crop Fairy to appear before or after daily earnings. She will select an area that contains crops and transform them so they can be harvested. Everything from a 1x1, 4x6, to a 5x5 area has been reported. It has also been reported that she could revive crops after the end of their growing season when they are supposed to be dead. When the Crop Fairy affects crafted seasonal seeds, (Spring Seeds, Winter Seeds, etc.), the crops will only be of only one type (out of the 3 or 4 possible), chosen at random.
In a random event after you sleep, a witch will fly over your Farm.
There is an extremely rare chance for a Strange Capsule to appear on the Farm overnight. If left alone, after 3 days it will appear broken, and its contents will have disappeared.
There is an extremely rare chance for a unique Stone Owl to appear on the Farm overnight. This owl is unrelated to the Stone Owl sold at the Night Market. The chance for this owl to appear follows the same rules as the Strange Capsule.