Treasure Hunt Party  Make invitations by photocopying a map of your neighborhood on a piece of paper and gluing it to a piece of hard paper. (poster board).  Decorate with colorful plates and cups with fish on them to follow the theme. Have everyone wear pirate hats that can be made with newspaper and painted black.  Buy a bunch of plain wooden treasure boxes at an unfinished furniture store.  Then paint them with assorted colors of acrylic paint. When the guests arrive, give each child a box to decorate with glitter glue and plastic jewels from a craft supply store. Write out clues for the treasure hunt and hide the clues around the yard.  The treasure chest is a Styrofoam cooler which you paint black.  You can use gold ribbon to trim the lid and the base of the chest. Then take some small rectangle shapes of yellow craft foam and glue on to the center of the lid in the front and the other directly below the chest to make the lock. Fill it full of gold-foiled covered chocolate coins, gummy fish, colored beaded necklaces (etc.)  Divide the guests into teams for the hunt.  Each team gets a clue that leads to the next five clues.  The last clue leads to the chest.  As far as the cake: Make a standard box mix cake in a 9x5 loaf pan.  When cooled, place cake on serving platter or a foil-covered piece of cardboard. With the long side of the cake facing frontward, cut cake in half horizontally at an angle.  Set the lid aside.  With a small knife, cut a 1/2 inch deep rectangular well from bottom half of cake, leaving a one inch border in front and a 1/2 inch border in back. Remove scraps and crumble with your fingers. Set aside. Frost the bottom half of the cake with chocolate frosting. (Don't frost the well) To achieve a wood-like effect, gently run a fork over frosting in a wavy pattern. Use canned vanilla frosting and tint it yellow for the borders of the treasure chest cake. Spoon yellow frosting into a pastry bad fitted with a 1/2 inch plain ribbon tip.  Set aside.  Insert pretzel rods vertically inside the well of the cake. This makes the treasure chest cake appear like the lid is partially open.  Fill well of cake with candies of your choice.  The gold chocolate coins work well or use Hershey miniatures and gummy life savers add color. For the lid, cut an 8 inch by 4 inch rectangle from cardboard and cover with foil. Spread chocolate frosting on top, bottom, and sides of top half of cake. Save 1 tablespoon of frosting for the keyhole. Place cake on top of foil covered cardboard for support. Place lid over cake, using pretzel rods and back edge of bottom cake for support.  Decorate cake with yellow frosting. Pipe a single line along bottom edges and double lines along top and center. For the appearance of nail heads, place M&M minis around treasure box and in a row down center of lid. Spoon remaining chocolate frosting in a resealable bag: snip off a small corner.  Pipe a keyhole with frosting. For sand around the cake, mix cake crumbs with graham cracker crumbs and spread around the cake. Fill with remaining candies, allow some to fall in the sand.  For a variety of candies, try using candy kisses, or starburst hard candies.  When the guests are getting ready to leave, fill their decorated treasure boxes with the foil-covered chocolate coins, Swedish fish, telescopes, and beaded necklaces in various colors.