This is a tasty and refreshing spritzer for hot summer days.
In a small saucepan, combine ginger, sugar, honey, and 1/4 cup water over medium heat, stirring until sugar is dissolved, about 2 minutes.
Place grapefruit juice in a pitcher. Strain ginger syrup through a fine-mesh sieve into pitcher. To serve, divide juice mixture among 6 glasses filled with ice, and top off with a splash of club soda.