Drink Pouch bags....Go Here for the instructions I used. The first one took about an hour because I was going between my sewing machine and the computer because I didn't feel like printing it out. The second was closer to 30 min.
These are easy to make in customized sizes, just add more pouches. The boys want a "cool bag" so I'm planning on making them each a lunch bag that will hold our new divided food containers.