Cover a wall inside or out with a large sheet of paper. Give a brief (We did valuing diversity), supply paints and brushes etc. Stand well back! Graffiti begins.
Lining paper, thick masking tape, Paint (liquid or aerosole), brushes. Cleaning rags/bucket water
Pre cover a wall with protective plastic/paper. Make a surface in protected area by putting up lining paper as big as is practicle. Cover floor below area to be graffitied and place paint/brushes in area. Give a talk about your chosen subject, discuss pros and cons, give plenty of tips and pointers on how the subject could be shown pictorially! Make sure you give clear instructions on what you do not want to see appearing on the wall. Let the fun begin. I did this with my Explorers and they had a great time ending up with as much paint on them as there was on the wall. A good way to get them thinking about what may be a seemingly boring subject.