We drink frozen fruit smoothies regularly and the kids LOVE them and think they are the best treat ever.
Just throw any frozen fruit you have in the blender, add some plain yogurt, milk and blend. Super delicious, 100% natural, no sugar added milkshake.
I usually also add some nutritional items to the kids smoothies because I love sneaking excellence in to their bodies.
Chia seeds, flaxseed, kelp powder, ground oatmeal, ground nuts, etc. Not necessarily all at the same time
and if you're just going for yummy taste and not necessarily nutrition boosting, the fruit alone makes that.