I have been making my own healthy ice cream. I puree fruit and then fill the puree into ice cream moulds. It makes for the most lovely ice cream, you don't even need extra sugar or cream or anything! It's a cheap, quick and easy recipe, and it's so satisfying to have ice cream on a hot summer day without feeling bad about eating it.
A friend of mine just slices bananas and deep-freezes them. Even less work!