In the bottom of a tall glass, combine mint leaves and simple syrup and crush leaves with the handle of a wooden spoon -- the more you mash the leaves, the more mint flavor you will extract. In a blender combine the simple syrup, ice, and bourbon and blend on the "ice crush" setting until ice is finely chopped and smooth.

Rub the rims of tall glasses with orange segments or a little simple syrup and dip glass rims in sugar, then fill with the frozen mint juleps and garnish with fresh mint sprigs.