My Favorite Plum's Cooking for Children gives me an excuse to brag about this Hawaiian Island Cake. I made it two summers ago for Sadie's Hawaiian Luau-themed birthday. We rented a small pavilion at Seneca Lake State Park, handed out fabric flower leis, and decorated with a blow-up palm tree (Oriental Trading Company), Shane's old surfboard, and tropical plates and cups. When the kids weren't gorging themselves on cake and chips, they ran around in the nearby "Sprayground."*
The recipe uses a cake mix (although there's no reason you couldn't make a batter from scratch) baked in an 8-inch, one quart ovenproof bowl and an 8-inch round cake pan. I used two mixes for a taller cake, resulting in three layers: the rounded top, and two 8-inch layers. I used the extra batter for some cupcakes.
I did make the buttercream from scratch. Separating a quarter of the frosting to tint blue, I used the rest to frost the top and middle layers of the cake. To illustrate water, I used the blue frosting, then added sour gummy fish for more visual appeal. The cake was topped with a crushed graham cracker-beach, the shoreline delineated with blue and green M&Ms. (I wanted to use that sugar candy molded in the shape of rocks, but couldn't find them.) Everything was finished off with plastic palm trees, hula dancers, paper umbrellas (all found on eBay) and an "Aloha Sadie" written in purple gel icing. Cake slices were accompanied by (what else) Hawaiian Punch.
After all that sugar, we let the kids burn it off by whacking the stuffings out of pinata.
*The very same spraypark that, the following summer, was host to a cryptosporidium outbreak. Whee! Summer fun.