It wasn't a huge destashing project, but I made an ornament out of Christmas cards that we received for the holidays. If anyone else doesn't like to just toss the cards they get, this is a good way to keep them around in a more useful way! This is the third year I've done this with our cards, so I'm going put up the previous ornaments too, with links to the general how-tos in case they inspire anyone.
This year, I modified this tutorial
to make it hang from a corner.
Last year, I used this idea,
but with a different shape, obviously.
And the first year, which I think is still my favorite, I made a ball like this.