Star Fruit

You don't have to peel them. In fact I have never eaten them peeled, but the texture of the skin is rather tough, and Star Fruit is good only if it is ripe. I have not found in ripe Star Fruit around here. Not sure how well your blender will cut it up. You may want to slice a few stars to throw in there, or put a star on top of the smoothie. Now that would look cool.

Great! I make my smoothies for looks anyway