Tried this yesterday and it was an instant hit with the young 'uns.....
400g frozen fruit (I used summer berries)
400g live yogurt
sugar or xylitol to taste (I used 4tsp)

Leave the fruit to once side for a while so it softens just a tiny bit....add all the yogurt and then blend with a hand blender or whatever...add sugar to taste, and serve straight away....gorgeous and doesn't need freezing/mixing every 4 hours to achieve ice cream....and can be as fattening as you want depending how sweet you want it.

NB: Xylitol is a sugar alternative (I found it in Waitrose packaged as Perfect Sweet near the sugar)

Recipe from Smart Food Smart Kids by Patrick Holford & Fiona Joyce McDonald, as recommended by Food for the brain....

Enjoy
Michelle