Use a black top hat as the centerpiece. Turn it upside down, and have a stuffed rabbit peaking out of the top. Multi-colored scarves, tied together, can cascade out of the side to add a splash of color. Use playing cards, taped together to decorate the walls and tables. You can also make your own using poster board and markers. Cut starburst shapes out of dark colored poster board, and write magic words on them metallic markers. Use words like "hocus-pocus", "shazam", "presto-change-o", and, "abracadabra".
Let your guests make a magic potion they can drink! The day before the party, freeze grape or cranberry juice in ice cube trays. At the party, serve clear soda or seltzer. Let the guests add the ice cubes to "magically" change the color of their drink. Serve magic wands. Dip pretzel rods in melted chocolate. Let the chocolate harden, then, using white icing, ice the very tip of the pretzel, to make perfect wands. Make and serve rabbit in the hat cupcakes. Bake a batch of cupcakes, and let them cool. Once they're cool, take them out of the paper wrappers, and frost them with chocolate frosting. Use white icing to make a band just below the top of each one, to make them look like upside down top hats. Make or buy rabbit shaped sugar cookies. Frost them with white icing and use pink gel frosting to make the noses and inside of the ears. When the icing dries, put one rabbit in each top hat, and serve.