We recently got a package in the mail, and almost as wonderful as the package was the Styrofoam is came wrapped in.
I'm not a huge fan of Styrofoam for several reasons (it can get messy, it's not environmentally friendly, etc.) but I just couldn't throw it away before we put it to good use.
We tried painting with watercolors on it. I was surprised at how well it turned out once the paint dried: And the kids had a great time jabbing my old pencil collection into the Styrofoam pieces:
There's nothing like playing with a new toy!