Slice off a small patch of rind so that the melon is stable. Draw a line all the way around the watermelon, length-wise, and about an inch above the middle. Draw a handle—two parallel lines across the top middle of the watermelon that is connected to your other line. With a sharp knife use a saw-tooth pattern to cut the handle and the openings on both sides of your basket. Lift out the cut-out chunks and make melon balls out of it. Also, carefully dig a couple inches of the watermelon meat out of the basket and make melon balls out of them. Try to get as many seeds out as possible—but think of the ones left as an old-fashioned seed spitting contest waiting to happen. Combine the watermelon balls with the other fruit and spoon into basket. Sprinkle with mini marshmallows.