Blender: Using Stuff - Compositing.

We'll use a file someone else build, and try to modify the final 'look' of the scene. Compositing nodes will alter the output to a toon style render. Enjoy!
Original scene by (and thanks to) Chris Kuhn.

You can see the result on the video below. As always feel free to experiment with the colors and settings for the compositing nodes (and scene). You could try to add these compositing nodes to one of your scenes and check how it'll look. Experiment!

Download the final .blend file from this link. Thanks again to Chris Kuhn for his awesome work on the original scene.