I spoke at our old church several months ago about being 'green.' One of my tips for getting started was to really just look at what you are throwing out and start there. One of the things I noticed that we throw out but couldn't figure out a way to reduce, reuse, or recycle was the orange juice carton. When I can't squeeze our own, which is all the time now, we go through about 1 carton a week.
Family fun magazine this month showed a project making cartons into little boxes for use with leftovers, in picnics, snacks, etc. They show adding sticky velcro to the top to close them up, but I didn't want to waste velcro so I cut some slits in one side of the top flap and created a little tab. It's worked out pretty well.
We took our new picnic boxes to the children's museum and they worked out great. We stuffed ours with hummus and crackers, fruit and cheese, and brownies. I rinsed them out and they are ready to go again. We are too, the museum was great.
Here are some closer pictures of my tab and slot system and the general assembly: