In my Elements and Principles class which is filled mostly with Freshman I like doing a Graffiti name tag. It is a great way to start off the semester, keeps the kids engaged and gives me time to learn names and ability levels.
I started out the lesson simply by showing a youtube video of how to draw graffiti letters. Then I demonstrated with my own name on the projector and had them work with me. After that they were off and running. They used black markers and colored pencils. We talked briefly about glazing to get the blending of colors. It took them about 3 days to finish these. Each day I would show some examples of graffiti at the beginning of class to keep their brains going.
Here's a few: