i make them up as i go along.
usually i have frozen bananas in the freezer (freeze whole in peel, when you want to use it, stick it in the microwave for a few seconds, then snip off the top and squeeze it out like toothpaste! Looks like slime, but tastes good, and its already mashed). I use them and whatever fruit I have on hand (plums, oranges, and applesauce are always hits), add ice if I want it like a slushy. I usually add dry milk and vanilla to blend the flavors....some OJ concentrate or honey if it needs sweet......milk or yougurt or ice cream....blend and yummmmm
One the kids really liked (of course I cannot remember exactly what was in it) was apples (or applesauce), milk, vanilla, ice, cinnamon and I think peanut butter! some times I remember to slide in some flax seed oil too.