Pinterest helped me find something for Adelyn to do for Earth Day last April. I'm just slightly late posting this. This idea came from the blog, "No Time for Flashcards" at this link http://www.notimeforflashcards.com/2010/08/puffy-paint-earth.html.
You can find the recipe there. You mix shaving cream with glue and food coloring. The kids play in it and then smear it all over the paper. It's a great sensory activity and then you can pick your favorite Earth songs to play along.