Fill the water gun with watercolors then shoot. This could make for a really cool summer craft/game. Have all the kids and parents wear paintable clothes then have a water gun battle of epic color. :) bet it would be more fun than tie dye.
"Glow In The Dark Pathway." GENIUS…Line a pathway with rocks painted in glow in the dark paint. During the day they “charge” in the sun and in the evening they reflect the stored light. Rust-Oleum Glow in the Dark Brush-on Paint.