We've been having a lot of boozy sweet-stuff this month at work (tequila choccies, boozy cakes, etc.) and my boss mentioned that his missus used to make vodka watermelon. I've not yet tried this but apparently it's great fun and fab for a party! Please note that servings are approximate and you can make this as boozy (or not) as you wish, but it's probably prudent to allow for a small bottle of vodka. You may need to turn the watermelon occasionally as my boss did comment that sometimes when they have it the vodka all falls to the bottom and some slices don't taste very alcoholic at all. I've heard you can inject the vodka into the melon as well, but if you're anything like me then you don't have a whole lot of needles lying about your house!