My guiding philosophy of writing, maybe even of life, is that the path to the truth runs through shame. So dig through your memory banks and write about the most shameful episode you can remember. The challenge here is to provide the reader the basic dramatic context, then to slow down and move moment-to-moment during the worst of it. This need not be for general consumption. It's more an exercise in radical disclosure.
Today's fiction prompt comes from fiction writer Steve Almond, whose most recent book God Bless America: Stories was published this week by Lookout Books.