Combine 2 Tbsp. bourbon and 1 1/2 teaspoons fresh lime juice in a cocktail shaker; fill with ice. Cover with lid, and shake vigorously until thoroughly chilled (about 30 seconds). Strain into a 10-oz. glass filled with ice. Top with 6 Tbsp. of your favorite ginger ale or ginger beer.
Drizzle with 1/4 teaspoons grenadine. with fresh lime slices or wedges. Garnish with fresh lime slices or wedges.
Note: If you can find them use good quality ginger ale and grenadine. I love Fever Tree and Jack Rudy's small batch grenadine.