Faith Durand at The Kitchn did a great post a couple of years ago on How to Make Creamy Ice-Cream with one ingredient - and that one ingredient was ripe, frozen bananas.
"If you freeze a banana until solid, then whiz it up in a blender or food processor, it gets creamy and a little gooey, just like good custard ice cream. I was surprised at this bit of kitchen wizardry; I assumed that a blended banana would be flaky or icy. But no — it makes creamy, rich ice cream."
This year she did another post this time with 5 different flavors.
All these recipes are indexed on EYB so you can add them to your Bookshelf. Flavors Original
I haven't tried it yet - but keep meaning to, particularly as my freezer space is half full with frozen bananas - as you say you can only make so many banana cakes!