This exercise was introduced to me by Emma Coats, a Pixar storyboard artist who worked on the upcoming movie Brave.
The rules are you choose a picture on the net and then board the next five shots in the story.
"Imagine this is a frame of a video on pause. Press play. What happens ?"
Here's the original photo (for the first shot) : http://sd-1.archive-host.com/membres/up/175457980037248337/Image_1.png