Glow in the dark egg hunt. Could spray paint the eggs with glow in the dark paint instead of using glow sticks. Also, doesn't have to be for Easter. Could be a fun night time scavenger hunt or other fun summer game.
Tween Girl Easter Basket Idea: Easter Egg Nail Kit
How to dye eggs with shaving cream, Shaving Cream SWIRL eggs, Easter Eggs, How to make swirled easter eggs - I did this. Let the shaving cream stay on at least 30 minutes! The food color came off after 15 and the eggs came out white