This short video (3:13 minutes) introduces complex adaptive systems and agent-based modeling concepts to middle-school students. It shows beautiful footage of birds flocking as an example of a complex adaptive system.
This link will take you to the playlist for the Project GUTS/CS in Science youtube channel, where videos for each module and for teaching and StarLogo Nova tips are organized.
A portion of a PBS NOVA video discussing the concept of emergence (or complex adaptive systems) where patterns emerge in nature where agents follow simple rules.