In a small saucepan, bring the sugar, 1/2 cup water, and ginger to a
boil over high heat, stirring to dissolve the sugar. Turn heat down low
and simmer, covered, for an hour. Remove from the heat, add the mint
leaves, stir to combine, cover and let sit overnight. The next day
strain the syrup through a fine mesh strainer and store in a glass
container.
For the mojito, muddle 2 sprigs of fresh mint in the bottom of a glass,
add the juice of ½ lime, syrup, rum and ice, top with seltzer, stir well
and top with a slice of lime. Refreshing as a virgin drink also.