Do a EK lesson on the sustainability of the Cork Oak tree...here is a company recycling them and making tiles from old wine corks! If you send them corks they will send you samples of the finished product...
http://www.yemmhart.com/news+/winecorkrecycling.htmMake a homemade calorimeter to determine how many calories are in a kids favorite foods using some...here is how:
http://www.seplessons.org/node/349Here is a fantastic online set of science experiments, many of which use corks...you can make one dance under glass using static electricity, use them to make home-made compasses, and burn them to make different colored flames...
http://www.arvindguptatoys.com/arvindgupta/vivian.pdfIf you are thinking more arts and crafts ideas, they make great homemade stamps, boats, wreaths, and stringing decorations on Christmas trees (saw a friend do this in college with Waaaayyyy too many

)
Just a few ideas...
BTW... You can make your own paper but I have never managed to get the consistency right!