Take a tip from the Thai, who know how to handle a hot day, and stir up a refreshing lime soda. To make this warm-weather thirst quencher, juice a lime into a tall glass, dissolve 1 tablespoon of sugar in the juice, fill the glass with ice, and top it with 3/4 cup (equivalent to half a 12-ounce can) of club soda or seltzer. To share with friends, multiply the recipe and make pitchers, ready for pouring straight or for mixing cooling cocktails.