We love this idea from Daily Danny, by the irrepressible Danny Seo: lining a pathway with beach rocks painted with luminous glow-in-the-dark paint. During the day, they charge in the sun, and in the evening, they reflect the stored light. A 7-ounce can of Rust-Oleum Glow-in-the-Dark Brush-on Paint is $7.79 at Blick Art Materials.