Crush graham crackers and place on a plate. Moisten the rim of each glass with a lime wedge and nestle the rim in graham cracker crumbs, set aside.
Pour the graham cracker crumbs in a shallow dish. Rub a lime wedge around the edge of a martini glass and roll the edge in the graham cracker crumbs. Chill the glass for 30 minutes or until ready to serve.
In a cocktail shaker combine the vanilla vodka, key lime liqueur and pineapple juice. Fill the shaker half full with ice and shake until well blended. Pour into prepared martini glass, garnish with a lime wedge and serve immediately.