Write a story about someone editing their work.
Write about a weapon.
Write about angels and demons before they became separate beings.
Write a historical fiction fairy tale retelling.
Where once there was a park, there is now only a gingko tree.
Write about it raining at an inopportune or surprising time.
Go learn a cool science fact and use that to inspire a story.
If you are a dog person, write about a cat. If you are a cat person, write about a dog.
Write about somebody having a no good, very bad Thanksgiving.
Write about a backpack and its daily life.