Snow Day #4?

Dyed Rice.  This one was super simple.  Put a cup of rice in a bag with one teaspoon white vinegar and your choice of dye.  Close the bag and agitate.

Spread damp rice on paper towels to dry.

Make kids go outside while rice dries.

 Allow the kids to use the rice however they see fit.  My girls had a tea party with blue rice tea.  It was delicious.