Place the banana and your chosen fruit into a blender and whiz for 30 seconds. Add the ice cream. Place the lid back on tightly and pulse the blender a couple of times on and off to break up the larger pieces of ice, before whizzing up to a semi-slushy milkshake consistency.
If you haven't got a blender, you can do as I have been known to do -- place the ice into a clean tea towel and bash the hell out of it with a rolling pin before stirring in the mashed fruit and the cream. It's good, but not quite as good. The 3 smoothies below can be made by following this basic recipe, using the listed ingredients as your chosen fruit.