I got Philippa an ice-cream-making-ball for Christmas, so occasionally we get ice and salt all over the kitchen and try and make some ice cream. Here's a really nice one that we made just this weekend:
You just need to squish all the ingredients together and then freeze them, in an ice-cream maker or probably it'd work in the freezer - just stir it every 20 minutes or so, and after an hour at most it'll be frozen.
You need to squish the berries so that they burst at least a little bit and so that some of their flavour comes out into the yoghurt. If you really want them squished, the best way is to mash the sugar and the berries together, before adding the yoghurt. But it's nice not to pulverise them completely.
The slightly tart blueberries and the yoghurt make a really nice flavour together.