(Based on a recipe from the New York Times.)
4 bananas
1/4 cup chocolate chips
1 1/2 Tbsp. honey
Chop bananas into 1-2" pieces and freeze for six or more hours.
Process frozen bananas with honey in food processor. When the banana mixture has achieved a soft-serve like consistency, add chocolate chips and pulse to mix without atomizing.
Eat immeidately or (better!) refreeze for a hard ice-cream like texture.
We expect that you could lots of interesting things along these lines. The Times suggests adding nutella or trying different fruits.