Prompt: Write a story. Cut the results in half. Then double them.
Prompt: Somewhere in your hometown, there’s an abandoned building. That’s your main character.
Prompt: Think of a type of story you’d sooner die than write. Do it the right way. But don’t start doing it “right” until page two. Try to make the shift natural.
Prompt: Go to your local grocery store. Watch the cheese section closely. There’s your story.
Prompt: If you've got an idea where you've either got too many people in space too small, or not enough people in a very big space, reverse the idea. Write the same story, but put lots of people in a big space, or very few people in a very small space.
Prompt: Make someone wonderful do something loathsome. Don't explain why, but make sure the reader clearly knows why.
Prompt: Destroy something everyone else is defending (newspapers, for instance)
Prompt: How far can your story safely go before you have to put a character in it?
Prompt: Construct a story backwards
Prompt: Tell a story that includes first, second, and third-person, omniscient and omniscient limited
Prompt: Give your character a defining tic or quirk and let that become the motivator throughout the story
Prompt: Write yourself into the story as a character