When I read Marcie’s sentence accompanying her Word of the Week, “The historian cannot understand the mysterious inscription on the ancient tomb,” I thought: 
Wouldn’t Marcie’s sentence, using “mysterious,” be perfect for beginning a story. Or you could replace “ancient tomb” with another word…gravestone, basement wall, closet door, rock inside the cave.  Also, replace “historian” with boy, girl, or younster(s)’ name.
What a perfect prompt for a story!  You could do this with many sentences you find in your reading.  Use them as prompts, changing to fit your needs.
(Haunted Tombstones image at Amazon)