In one of my Tips & Tricks posts, I talk about starting with an interesting title and creating a story from there. Sometimes a title can be relatively ambiguous, and other times it can convey a very clear picture of what elements are involved in the story.
Take a vague, but interesting title, and proceed to write two or three different short stories that coincide with it (perhaps start with flash fiction to make it easier). Try to make them contrast as much as possible, yet still fit with any themes / tones / images the title might imply.