Here's a good formula: take aromatized or fortified wine, serve on the rocks. Wanna get fancy? Add a splash of soda. (Ok, it's not that fancy. But it is delicious.)
Serious Eats New York editor Max Falkowitz discovered this easy cocktail on the recommendation of his server at Hearth in the East Village. They key to the drink is a hefty pour of wonderfully bittersweet Cocchi Americano (pronounced "COKE-ey", not "COACH-ey"), which is made with fortified Moscato di Asti that has been infused with cinchona bark, citrus peel, spices, and other botanicals. Lightened with a bit of soda, it's orangey with just enough edge to keep it refreshing. You can increase the soda or serve it almost-straight, depending on your sweet tooth and your thirst.
You hardly need a recipe, but here it is: Cocchi and Soda »