The Seelbach Cocktail: bourbon, triple sec, bitters and Champagne.
The “daisy” is a sour made with triple sec or orange curaçao instead of straight sugar. The Margarita is one of the most famous examples: white tequila, lime juice, Cointeau and sugar.
The Crimson Slippers Cocktail taught me that rum and Campari are an astonishing, and nearly perfect, combination. Just make sure it doesn't get too sweet.
The little-known Campden Cocktail — gin, Lillet and Grand Marnier — makes a pleasant, cold splash for a spring evening.
The Vermouth Trilby Cocktail: dry vermouth, Cointreau and bitters, with a whiskey float.
The Countrypolitan Cocktail: bourbon, lime juice, demarara syrup, Grand Marnier and Pama. A whiskey-based alternative to the Cosmopolitan.