Combine the water and sugar in a medium saucepan. Bring to a boil and stir until all the sugar has dissolved. Remove from heat and allow to cool completely.
Once cooled, store in a mason jar in the fridge for up to one month.
Mojitos:
Squeeze the juice from the lime quarters into a cocktail shaker, then throw in the quarters. Add the mint leaves and the blueberries. Using a pestle or the back of a wooden spoon, muddle the limes, mint, and blueberries together.
Pour in the rum and add a bit of the simple syrup. Place the cap on the cocktail shaker and give it a quick shake or two.
Fill two glasses or pint jars with ice. Pour the strained mixture evenly into both glasses. Now go ahead and dump 2 of the lime quarters and some of the mint leaves into each glass. Top with a splash or two of ginger ale.
Give it a quick stir and taste. If it is not sweet enough for you, add in a little more simple syrup and stir.