I’ve often picked up a stray object, tossed it into the middle of the room and asked participants to write in response to it. In one case, it was a lost glove I found on the sidewalk. It's fascinating how a found object can evoke the physical and emotional attributes of the person who lost it, and their personal history.
I also like to ask participants to write about "home." What is it, where is it, what does it look like, how does it feel to be there—or not be there . . .