Wash your hands with soap and water, then gather all of your kitchen gear and ingredients and put them on a clean counter.
Put all the ingredients in the blender. Put the top on tightly, turn the blender to a medium setting and blend until the ice is chopped and the mixture is smooth, about a minute.
Serve right away - or store in a thermos or covered in the refrigerator, up to 4 hours.
Think ahead: Freeze the banana ahead of time for a thicker, slushier, smoothie!