Stir together sugar and 1/2 cup water in a small saucepan over medium heat. Bring to a light boil, and cook, stirring occasionally, 3 minutes or until sugar is dissolved. Remove from heat; add sage leaves, and let stand 5 minutes. Remove and discard leaves.
Stir together syrup, club soda, orange juice, and bourbon in a large pitcher; add ice cubes to fill. Serve immediately.
I made Kentucky mimosas for Sunday brunch, and there wasn't a drop left. My husband wanted more bourbon in it, but a guest added orange juice to mitigate the bourbon in hers. I think we'll be making these mimosas a lot this summer!