How to Make It
In a small saucepan, combine the sugar and water and cook over high heat just until the sugar has dissolved. Let cool to room temperature.
In a large pitcher, combine the sugar syrup with the mint leaves and lime wedges and muddle well with a wooden spoon. Add the rum and stir well. Strain the drink into another pitcher.
Fill tall glasses with cracked ice and pour in the drink, filling them about two-thirds full. Top with Champagne, garnish with the mint sprigs and serve.