hedgehog fall leaf craft - I did this with my son's class and it was a total hit. I'd recommend using leaves that aren't brown yet, as the brown leaves are more brittle and hard for kids it work with.
DIY Wall Decoration with CD-paint a solid color and then use scratch art tools to expose the prismatic silver underneath.
For Camping Week at School! The Playful Garden- Handprint S'mores (my kids are too old for this now, but could use chalks or oil pastels and do a lesson on how to draw a fire)
Straws and tile crosses!
Snap painting with rubber bands! Sounds like an amazingly fun and messy activity!