if you are having a party with what remains of the summer, I commend to you very highly the following.
Buy the biggest watermelon you can find. Really. Shave one side til it lies flat without rolling, and cut a neat oval lid. Spear a teaspoon through the lid to make a handle. Carefully hollow out the watermelon as you would a halloween pumpkin, reserving all the innards.
Slice oranges and lemons and chop up some peaches, or other fruit you happen to fancy, in quantities which seem appropriate. Mix 3 litres cheap red wine with 1.5 litres each of orange juice and lemonade (add the fizzy stuff just before serving). Add cinnamon and nutmeg to taste, and a little sugar if it still needs in. Chuck in a small amount of the chopped watermelon innards, and stick the whole lot into the watermelon, in the fridge.
This is guaranteed to make your guests 1) go ooooooh a lot until 2) they fall over drunkenly.
[What to do with the watermelon? Some can be chopped up neatly for eating. Take what's left, stick it in the blender or through a mouli-legumes, to make a lovely pink juice. Juice some limes, and make a watermelon, lime and tequila cocktail garnished with lime slices and, if you wish, a dash of ground chilli.]