What is hint fiction? The basic definition is that it's a story consisting of less than 25 words (excluding title). If you'd like more than just the basics, check out Robert Swartwood's essay on the form he has coined.
Swartman is also sponsoring a hint fiction contest, with Stewart O'Nan acting as the final judge. The deadline for your brief stories is midnight on April 30th. For more information, check out Swartwood's blog post.