In our book and often in our talks we discuss a technique for thinking through and documenting detailed interactions in a user experience. Just arrange the interesting moments in a grid. List the "actors" (user interface elements) vertically and the events horizontally. The cells in the grid become the interesting moments.
With the classic example from the of drag and drop there are at least 96 interesting moments (6 actors X 16 events = 96 interesting moments).
About a month back I gave a talk at Zurb, a northern California design firm, in which I discussed this technique. On Friday I was pleasantly surprised to see they had already taken the idea and used it in a new product they announced last week -- BounceApp -- which was featured on TechCrunch.
Check out their article on 110 Interactions for Editing Annotations on Bounceapp.com.
Nice application of the grid.