If you have time to pick and choose your building materials, and a place to store them, the plastic bottles can be used for walls.
http://izzym.hubpages.com/hub/How-to-Build-a-House-Made-from-Plastic-Bottles
I have also seen some pretty greenhouses made from clear or green plastic bottles. They would make a great sun-room. You can use glass bottles stacked and mortared together for a wall that lets in light.
If you can get the scrap paper and cardboard bailed you could use them in a straw bale type construction house. It would need to be treated like R. Scott mentioned to prevent pests.
Sorry for the random stream of consciousness, but anything clean and nonreactive could probably be used in some for of construction.