I've been on an apertiff-flavored booze-digestif creating binge for a couple of years now. Most of what has been made has turned out pretty well [except for something involving fresh thyme that was not quite fresh enough soaked in grain alcohol--think seriously medicinal].
This summer I've come up with one thing worth sharing---grown-up fresca. Anyone remember fresca?--that grapefruit flavored soft drink that isn't around anymore? Well take a fifth of cheap vodka and the zest from about 4 grapefruits. Soak for about 3 weeks until the grape fruit is pale yellow and the vodka is extremely yellow and fragrant. Strain. Store infused vodka in the freezer.
To serve, pour 1 1/2 - 2 jiggers of vodka into a glass and top with very cold sparkling water of your choice. Add a slice of fresh lime. Ice cubes would probably be nice but we were all out. Keep drink away from the kiddies.