When you get really ripe bananas, throw them with the peel on, right in the freezer, so you have a supply on hand. To use banana, run hot tap water over it, and then peel with knife.

2 frozen bananas (or more or less as desired)
Big blob of orange juice concentrate
Handful of frozen strawberries or blueberries
Water to fill up the blender
Anything else you like

Put all ingredients in your blender, a little at a time, depending on how powerful your blender is. Make sure to put in a lot of the orange juice concentrate. Experiment with different amounts of the different ingredients. You can't really go wrong. More water will make a thinner drink. Less water will make it thick.