Pimm's cup is a very English drink. It is one of two traditional drinks at Wimbledon and many other high profile British events, the other being champagne. Its base is Pimm's No. 1, a liqueur invented by one James Pimm in 1823 London. The cocktail could hardly be simpler: 1.5 oz of the liqueur over ice, top off with lemon-lime soda or, the preference at our house, ginger ale. Garnish with lemon. There are more complicated recipes in bar books, usually including additional garnishing with cucumber and mint, but the basic formula on the back of the bottle suits us just fine. The liqueur itself brings a spicy, fruity flavor to the party - evokes cinnamon for me.
American Bar by Charles Schumann includes three Pimm's recipes. They list our drink, with ginger ale, as Pimm's Rangoon. Pimm's No. 1 is mixed with lemon-lime soda, Pimm's Royal with champagne. My wife just bought a new bottle of the liqueur so we may well have the chance to try all three.