Place one cup of fresh juice in a blender, add one cup of spinach, two mangoes and 1/4 cup of mint in a blender and blend. The trick to making a good smoothie is to begin by putting the liquid in first, helps the motor's work a little easier and your blender last a little longer. The end result is really good.
You could also replace the mango with an avocado for variety and still get an amazing tasting smoothie.