Combine the bourbon, half-and-half, and vanilla in a gallon container. Add as much syrup as you need to attain the desired sweetness. Chill thoroughly.
Pour into chilled glasses, sprinkle with ground nutmeg, and serve.
Combine the sugar and the water in a small saucepan. Stir and boil until the sugar dissolves and the liquid becomes slightly syrupy. Cool completely before using.
The syrup will keep indefinitely in the refrigerator.
Yield: about 1 cup