In a pitcher, combine the cranberry juice, vodka, Amaretto, and orange juice. Cover and chill until ready to serve. (You can do this 1 day ahead- keep refrigerated).
To make 2 drinks: fill a cocktail shaker with ice cubes. Pour in 1 cup of the vodka mixture. Cover and shake vigorously. Strain into 2 cocktail glasses. Garnish each with clementine or orange slice, if desired. Repeat 3 more times with ice cubes, remaining vodka mixture and clementine/orange slices.