Pastel art with a watercolour and salt wash, the ideas are endless. Also this site has lots of fun classroom art ideas. Do this with the Native American legend book "Thirteen Moons on a Turtle's Back".
Masking tape rings - exercise for drawing overlapping shapes; this was a fun project and the kids loved how it turned out! 7 & 5 yo needed some help visualizing the overlapping rings and erasing the correct lines