I made a fabulous almond cake that I found here on chowhound. I simply subbed the matzo cake meal in for the flour. Note that this does not always work, and cake meal can impart some unpleasant flavors to baked goods, but it was undetectable in the almond cake, and the cake was FABULOUS. Fortunately no one else in my family seems to like almonds so I got to eat it myself :) Here is the link:
It keeps very well from Passover to Passover (I have a sponge cake in the oven right now made with matza cake meal I bought last year, and the one I made last week from the same meal came out beautifully), so if you're planning to do any baking for next year's seder, you can save it in a tightly sealed container in the back of a closet somewhere.
You can also dredge stuff in it before frying, instead of flour.
My great-aunt Irene's Pesach sponge cake, an excellent example of the form:
10 eggs, separated
1 3/4 cups sugar
1/3 cup fresh-squeezed orange juice, or the juice of one very large orange
Juice of one lemon, or 3 tablespoons
3/4 cup matza cake meal
1/2 cup potato starch
Preheat oven to 350 F. Whip egg whites with 1/4 cup sugar until they form stiff peaks, and refrigerate. Separately, beat yolks with 1 1/2 cups sugar until thick. Add orange and lemon juices, and beat until thick. Mix in matza cake meal and potato starch. Fold in egg whites. Bake 55-65 minutes in tube pan, or until tester comes out clean. Invert cake in tube pan immediately after removing from oven, and leave it upside down until cool. (We used to use a wine bottle for this, inserting the top of the bottle into the hole in the tube pan, but the hole in modern pans is usually too narrow, and I end up balancing it carefully on top of some platform, usually an upside-down vase with a broad base. )
This doesn't use up much, but I adore this cake so much I often make it when it's not Passover.
9 eggs, separated
1 cup sugar
1 pound walnuts in shell or 7 ounces (2 cups) shelled, chopped VERY fine
1 teaspoon vanilla
2 tablespoons Passover cake flour (Matzoh Cake Meal)
Beat yolks in sugar til foaming. Add cake flour, salt, and vanilla. Add nuts. Fold in stiffly beaten whites. Pour into ungreased tube pan. Bake 45 minutes at 350°. Invert and cool.