In a small saucepan, bring water and sugar to a simmer. Cook until sugar dissolves. Remove from heat and let cool.
In a large pitcher, fill with ice. Stir in simple syrup, vodka, juice, lemon and lime slices.
*for kid-friendly version, omit alcohol.
Split beans lengthwise and add to vodka bottle. Let infuse overnight in a cool dark place. Strain into another sterilized bottle.