When fruit is perfectly ripened and freshly harvested, you don't need to do a lot with it to make it delicious. I'm taking a beautiful watermelon and puréeing it into a juice. The only other ingredient is a few mint leaves.
After you peel the watermelon, don't automatically throw the rind in the compost bin -- pickle it! Sweet Watermelon Pickles are especially tasty served alongside cold cuts.
Then comes the biggest hassle when dealing with watermelons -- removing the seeds. (And trust me, you don't want to have too many stray seeds find their way into the blender!) There are seedless watermelons out there, but I find them to be much less sweet than the traditional fruits. You can decide for yourself -- convenience versus flavor!
If you want to jazz up this recipe, try some of these ideas: