I've always wondered "WHY is there a table with pies and cakes handy for a pie fight?" The few parties I've been to with a dessert table, had SLICES of pies and cakes, not whole pastries.
And then I hit on it: A bake sale. Throw in a little rain to ruin the sales and merchandise and Somebody Must Be Blamed. Preferably several somebodies, not wearing too much.