Think of it as the all-American version of Venice's frosty-fruity sgroppino cocktail. Instead of the Italian version's lemons, freeze the flesh of a watermelon and puree it to an ice-cold slush. Add vodka and Prosecco to the mix (or leave them out altogether).
Don't overlook the importance of the accompaniments. Eggs, tuna, cured meats, and other protein-rich items make the otherwise light-bodied soup a satisfying meal. Set everything out in separate dishes, and let everyone pick and choose among the offerings.
Sweet potatoes are in my seasonal repertoire this time of year, so I'm always on the lookout for new ways to enjoy them. When roasting, leave the skins on for greater nutrition (and better texture). High heat muddies the fresh flavors of the herbs and lemon zest in pesto, so top it on just before serving.