Before packing lunches, pour juice into a zip-top plastic bag and freeze. At lunchtime, the tip of the bag can be opened, a straw inserted, and the juice sipped. Be sure to pack the straw in the lunchbox.
Freeze juice cans or boxes before packing them in lunches. This will keep them cold and will help keep the rest of the lunch cool as well.
Pour the syrup from canned fruit into ice cube trays and freeze for later use. They can be added to punch, etc.