It was a long day in the sun. The fumes of spray paint came in waves, mixed with the smell of saltwater from the bay.

Or, put Wii controllers into empty paint spray cans, give the cans to a group of kids who can then "spray" the walls of the room with virtual graffiti.

The ordinary doodle liquid and paint can be erased easily or removed with menstruum and have no affect to the coating surface.