A popular theme that works well for either a boy or a girl is a clown or other circus_related cake. They are usually very bright and colorful, which makes for instant attraction and a great focal point for a party table.
Decorate_your_own Cake: Moms who hate decorating kids birthday cakes will love this suggestion __ provide the basic ingredients (cupcakes, frosting, piping bags, spreading knives, small candies, etc.) and let the birthday boy or girl and his/her guests decorate their own cupcakes! Just lay down a plastic tablecloth and provide plastic aprons for each guest to minimize the mess!