Click the image for a great site with lots of fun art projects.
I love this project because it is easy for all grade levels. Basically it is ONE line that does not cross over itself. Straight, squiggly, curvy, whatnot, just cannot go over another line and should fill up the page. Once the page is full, draw some geometric shapes and chose similar colors to color each shape.
To me the circles looked like planets. If you are doing a space theme have the kids draw circles in different sizes and tell them what colors to do for the different sizes and they could cut them out and glue them onto a piece of dark blue construction paper. Use yellow or white crayons to add stars!