"Textured Painting - Natures Paint Brushes" This is not just art, but art in nature! Go on a nature walk to gather 'schtuff!' Then use what you gather to create art or As art!
fairy soup - happy hooligans - outdoor sensory activities for kids. This is also a free activity you could consider mentioning to parents; a trip to the local park and then play at home. Also called a messy mixture, or "perfume making"
A fantastic outdoor art idea that makes great use of loose parts found in a forest: clay faces on tree trunks! My son loves the funny faces people put on trees, now I can let him make his own :)
Counting and Grouping (Kindergarten)