What to do with a Bunch of Envelopes?

I am thankful that I work in a building and community where people ask the art teacher if they want something before they throw it away.  We love to recycle here in the art/tech labs and are lucky to have enough space to store all of the junk so bring in your tired, poor, huddled art supplies and we will accept them graciously and figure out a way to make something with them.
Perfect example:  Someone a couple of years ago donated nearly 1 a thousand white 14x10 envelopes.  We have used them for the usual storage of classroom resources, and the occasional ghost or two around Halloween, but this is the first time I ever thought about stuffing them!
The Kindies needed a good soft sculpture project that could tie into some of their standards, so I thought we might make snowmen out of the envelopes.  In hindsight, I could have given them more than 1 envelope and we could have made the sections of the snowman work, but the project turned into more of a Pillow Pet than a snowman.  When the kids actually are covering the goals you had planned for them, subject really isn't that important, so I went with it and it turned out to be a lot of fun.  The Kindies used markers and foam shapes to adorn the face and body region and then did the same to the construction paper legs and arms.  If we could have spent more time on them, I am certain we could have used construction paper scraps to add clothing and hats as well as hands and feet, but for the most part the kids had fun and learned some valuable sculpting skills along the way!