To whet your appetite and keep your writing fingers limber, take a good look at the photo, or let a prompt settle in your mind. Set a timer for a reasonable amount of time, be that five, fifteen, or thirty minutes. Then start writing.
Write the story of a fireworks display gone terribly wrong, but give it a happy ending. Then write it the opposite way.
Write about your favorite holidays that you celebrated as a child. What were the elements that made them special? How do you incorporate those elements into your life today?
Pick a historical event and write about how it still affects our world. What lessons can we apply to life today?