The last and first time I wrote a story and won a prize for it was in school - a short detective story contest sponsored by The Assam Tribune. I borrowed part of the hero's name from the hero of Jatayu's books - Jatayu being a fictional character who's himself a writer in Satyajit Ray's superb Feluda series.
Speaking of short stories, last year Wired magazine asked leading writers to come up with the shortest stories they can think of. Some of the best are here.
Then there's the Asimov edited anthology of really short sf stories - not able to find my copy right now. The ones in that were not one-liners, but mostly one-paragraphers and one-pagers.
Coming back to short stories of 'normal' length, my favourite ones in the sf genre remain
- One-Face - Larry Niven
- Chrysalis - Robert Reed (more like a novella)
- Most of ones in Stephen Baxter's Vacuum Diagrams
- Most of the ones in The Collected Stories of Greg Bear
