I love smoothies. Here's one that I've been making quite regularly lately:
handful of ice cubes
1 to 2 cups of low fat milk
1 Dannon Pure yogurt
2 Crystal Light packets (usually one is Energy and the other is Fruit Punch flavor)
We have a BlendTec ... I choose the "smoothie" button - it mixes on super high for about 40 seconds.
It is about 340 calories.