I liked this simple 1-2 day project with 1st graders. I made them follow my directions, but everyone's still turned out different.
-Start with one large circle
-Make a circle go half-way off the page (cropped)
-Connect a line from the edge to one of the circles
...and the list goes on and on. Voila! They come out with some cool creations, outline them in sharpie, and color in using anything you'd like (we used glitter and regular crayons). They had to leave at least 3 spots white.