Saw this activity a while back on So this is English.... You can click the link to read the full activity, but basically the idea is that you show students a picture for a few seconds and then get them to describe it. I have done similar things in the past and it works really well, especially if the picture is interesting and has lots of weird details. Students start arguing about what they really saw.
I posted once about my first course as a teacher and how my poor students suffered grammar pounding. The one good thing I ever did in that class was the first class.
I found a funny crime scene photo in a textbook (tried to find something good that works on Google but failed to do so), with the suspects wearing Groucho Marx glasses and crazy wigs. If I remember correctly, the victim was killed by safety scissors or a toilet brush or something ridiculous. I flashed it to one student for a few seconds and asked her to say what she thought happened. Then I showed it to another student who could add details or contradict the first students' account. After showing it to three or four individual students, I gave copies to the students in pairs and had them come up with a story of what happened and why.
By showing it to individual students first, I piqued the other students' curiosity and started a dialogue among a small group of students first as the students who saw it discussed what they had seen. At the same time, because the picture was weird, other students could jump in--What do you mean he had pink hair? He had a stick in his mouth? Was it a cigarette? And then I turned it into a basic story-telling/writing exercise for everyone.