Chris and I love to make smoothies in the morning. Sometimes we do a protein smoothie with banana, almond milk, peanut butter and protein powder. Other times it's fruit juice, a handful of greens and frozen fruit like mango and pineapple. Lately my favorite combo has been orange juice with frozen mango and frozen pineapple. We try to always keep a couple bags of frozen fruit in the freezer for smoothies and when bananas start getting too brown we put them in a ziplock bag and freeze them for smoothies.
A friend of mine showed me the genius idea of freezing leftover smoothie (or making a big batch and portioning it out) in glass jars. I've also tried freezing smoothies in ziplock bags but transferring thawed smoothie to a jar can be messy.
The single serving smoothies in jars can be heated up in the microwave for breakfast or taken to work as a snack. Often I'll take a jar of frozen smoothie in the morning and then let it thaw on my desk (on a paper towel) and by the time I need a snack it's soft enough to eat.