1. GIVE 'EM THE ROYAL TREATMENT
Mermaid princesses and aspiring sea kings need proper toppers. To make one, start with a sheet of card stock large enough to wrap around your child's head. Draw a tiara or crown shape (or print our template). Affix shells with a layer of tacky glue. While the glue is still wet, sprinkle on a mixture of sand and glitter to fill any empty spaces. Let the glue dry, then fit the crown around your child's head and tape it closed where the ends overlap.
2. BOTTLE 'EM
This mini ocean made major waves with our kid testers, who loved to send the shells, sand, and water tossing and tumbling. The project starts with a clean plastic bottle (ours is an 18-ounce beverage container). Pour in 1/4 cup of sand and add a handful of small shells (we used ten). Mix a drop of green and a drop of blue food coloring into 6 cups of water, then use the tinted water to fill the bottle halfway. Add a pinch of silver glitter. Fill the rest of the bottle with mineral or baby oil, leaving as little air space at the top as possible. Run a line of hot glue around the inside of the bottle cap, then quickly screw on the cap to create a spill-proof seal.
3. MATCH 'EM
Gathered shells hold the memory of a day at the beach -- and they can make an unusual memory game too. Select at least 12 large shells of the same type (clam, oyster, or scallop shells work well). Using duplicate sets of stickers, create matching pairs by affixing the stickers to the insides of the shells. Brush a thin layer of Mod Podge or diluted white glue over the stickers and let them dry. To play, lay the shells in rows with the stickers facedown. Players turn over any two shells. If they match, the player keeps them and takes another turn. If they don't, they're turned facedown again, and the next player gives it a try. The player with the most shells wins.