I saw on Pinterest this GREAT idea of having Harry's letter from Hogwarts shooting out of the fireplace. We made 25 envelopes. I used fishing line and lots of tape. The wax seal makes the envelopes heavy on the wire so I recommend buying strong fishing line. Hanging the letters was a little tricker than I thought. We used push pins to attach to the ceiling and tied the fishing line to the grate inside the fireplace.
I wanted to do the Sorting hat because that is one of my favorite parts in the book. I hung up these signs near the entry way. No hat needed.