Unclutterer and Lifehacker have reported on a binder clip use by Christine of Compass and Coffee Spoons. Christine took three binder clips, and put labels on them saying “To Do”, “To File”, and “To Pay”. She uses the clips to hold papers that need to have one of these things done and hangs them on the back of a closet door.
I've delayed several weeks in posting this because while I'm happy to see binder clips being used, holding papers together is not exactly an innovative use for them.
Adding, finding and removing papers from a cut-out envelope is much easier and reduces the risk of everything falling onto the floor each time you add or remove a paper.