Who lives here?

Anyone faced 2nd and 4th grade classes?  Drawing or teaching? Any ideas on lessons that last less than 15 min. and can engage 20 to 30 students?  Please let me know.

 Thinking about some sketch pages that ask kids to think about character sketches and storytelling in a fun way.  I am taking environment thumbnails and asking the class to add story and character designs and explain how they are related.
I want to show sketching techniques as well as get them thinking about story.....