I immediately started looking into it. There are quite a lot of different tutorials and inspirations out there, but I was drawn to a few that seemed to be the most fun to make.
• How To: Stormtrooper Helmet From Milk Jugs on Make.
• Milk Jug Decorative Window Crafts on Alphamom.
• Halloween ghosts on The Krazy Coupon Lady (admittedly we turned that one into a glowing super hero really quickly).
• Milk Jug Bat Masks on Filth Wizardry.
• Milk Jug Igloo from Mrs. Meacham's Classroom Snapshots.
(Images: As credited above.)