This milk jug reading Igloo was made with 430 milk jugs by It took about 4 ppl and five hours to build. It now resides at Down Town Orlando's public Library. This is such a fun craft to make for a class room/library. Kids absolutely love it.
Many creative designs show how to recycle plastic bottles. Plastic recycling helps decorate house exteriors and add nice accents to garden design on a budget. Plastic bottles can be turned in numerous useful and decorative things.
Bottle Bank via Martha Stewart: transform a used plastic bottle into a cute piggy bank. Could use same idea to made little containers for kids to store their collections too (use bottle with wider opening and don't make slot)