Have you ever written a piece that became a form, or even a genre, you hadn't planned on writing in? Or do you choose a form/genre in advance?
Most of my short stories have started with vaguely remembered dreams. The usual sequence goes like this:
- Wake up from a vivid dream
- Get out of bed, and write down notes on what I can remember
- Go back to bed
- In the morning, look over my notes. If it sparks something interesting, continue fleshing out the story. Otherwise, set it aside until the next wakeful night.
- Repeat until the basic framework is written.
At that point, if the story is viable, I finish it. As I didn't consciously plan the story, they often cover genres I don't normally read or write about. My first short story was a Noir-type, the second a modern update of a well-known story, and the one I'm writing now is science fiction (I plan to enter the Dark Matter anthology contest - wish me luck!)
Short stories are the perfect vehicle to experiment with form or genre - if you screw 'em up, you haven't wasted much time on the effort. and, I'm of the belief that ALL writing - even those projects that never get finished - teach the writer some technique or piece of craft that he/she/xe needed. Practice is never wasted; you have learned something on every session, even if it's what NOT to do again.