One of my biggest frustrations is when I (rarely) walk over to the work printer (unfortunately, you sometimes need to print) and see a pile of pages no one bothered to pick up. Especially when it's a private email or reminder you know doesn't need to waste a tree's life. I call this disorder WPS, or Wasteless Printing Syndrome. WWF format is an attempt at the WPS solution, since the recipient CAN'T physically print the page. You can easily visit the (find out where, after the jump!)
You know the obvious recyclable materials - plastic water bottles, cardboard, tin cans etc. - but don't forget about the not-as-obvious items you're through with that can be re-used.