In an 8"x10" dish, put 4 cups cut rhubarb and 1 cup strawberries. Sprinkle with 1 small box strawberry Jello, 1/2 cup sugar, 1/2 cup water and 1 small box white or yellow cake mix. Drizzle with 1/3 cup melted butter. Bake at 350 degrees for 45 minutes.