much-madness and I were discussing fiction prompts the other day, the kind used in ficathons, list challenges and other venues. We noted that they can be as tiny and generic as "pink box" or "catch-22" on the one hand, or as large and specific as that HP assignment
Leela_cat received or the Dark N&N Yuletide challenges, on the other, but that they usually fall somewhere between. Clearly, you want to give enough of a prompt to spark the writer's imagination, but not so much that you end up stifling her. (I heard somewhere that it is the longest, most detailed prompts that get defaulted on the most often.) Lines of poetry, song lyrics and other quotations are popular prompts.
A few years ago, trying to get myself writing, I copied out the HL "15-Minute Challenge" prompts, stripped out the character names, and tried to use them to spark my imagination elsewhere. I did manage to get one worthwhile story out of them, after two tries, and this gave me much appreciation for the utility of prompts, as did the "St Nick to St Lucy Challenge" experiment last month (was that only last month? golly!).
Do you have opinions you would like to share about what makes for a good fiction-writing prompt? What to include or avoid? How short or long?