For the sour mix: Combine the lemon juice and Simple Syrup in a glass and stir together.
For the emerald isle: Fill a cocktail shaker halfway with ice. Add the vodka, rum, Irish whiskey, blue curacao, 3/4 ounce of the sour mix and the orange juice. Shake once and strain into a Collins glass filled with ice. Garnish with the lime wedge.
Put the sugar and water in a small saucepan. Cook over low heat, stirring, until the sugar dissolves. (Alternatively, heat in the microwave.) Store in a sealed container in the refrigerator.
Recipe courtesy of John Green