Our bartender mentioned that in the summer months when folks are lingering on the patio for a longer amount of time, they'll often make ice cubes out of the tonic so that when they melt, the drink stays cool but full of flavor. The same could certainly be done with ginger beer or any mixing liquid (that doesn't have a high alcohol content, of course). For me, this was one of those 'why didn't I think of that sooner?' moments. We have a tray of tonic ice cubes in the freezer right now, and I'm never turning back.
Related: Straight Up: DIY Simple Syrup
(Image: Megan Gordon)