All around my hat...
Pick a hat and use it to find your way into a character and a story. What's the story of how this person got the hat? How might the character's demeanour or self-perception change when the hat goes on? How might another character's perception of them change?
What hats have you got in your own house? Get them out and have a good look. What fictional characters might wear your hats?
If you're working on a novel, put a hat on a character every now and again and find out what it reveals – or conceals – about them.
Tell the story of a life through the different hats.