One writing exercise from the book that I liked was this one. I think it would be fun to try with a group:
"Look through a page of newspaper want ads. Imagine the person who placed the ad to sell the ticket, car, unused wedding dress, etc. Conjure up that character and the story line that led him or her to do this. A second group should brainstorm the character who wants to buy the object, along with that person’s motive. Individually, write the scene of a meeting between the two characters."