Ok, maybe I start:
- I'll visited the original Great Hall of Hogwarts!
- I've seen performing & met Alan Rickman & Fiona Shaw & got their autographs!
- I did a painting of Severus Snape & Albus Dumbledore!

Ok, here's mine, but I probably won't remember all of it just now :P

- I made a Hermione photo-shoot with a friend
- I made a HP Lego movie with the same friend
- I made a huge HP board game (about 4m² I'd guess) with the same friend
- I made two normal-sized HP board games and a HP card game on my own
- I made my own wand
- I started exercise books for each of the Hogwarts subjects
- I made new book covers for some books I never read to make them look like Hogwarts books
- I started to write the text of a Hogwarts school book
- I've got my wall covered with self-drawn portraits of HP characters (movie versions)
- I write HP fanfiction
- I compose a movie soundtrack for the (admittedly inexistent) movie of one of my fanfictions
- I made promotion posters for the same inexistent movie
- I started an audio-book of one of my fanfictions (read by me with a German accent :P)
- I learned all of Hermione's lines from Philosopher's Stone by heart and there's still a very embarrassing video of me reciting them
- I fell for Alan Rickman and watched all of his movies
- After reading HBP I made a list of indications to support my theory of how Snape could still be on Dumbledore's side
- I bought lots of useless HP fan-stuff
- I had some really crazy HP dreams (the last one just 2 days ago)

There are also a few things that are too private to post here and probably quite a few things I forgot to mention and of course lots of stuff that isn't worth mentioning because most HP fans do them.

And last but not least a friend and I are going to watch all the 8 movies in a row when the last DVD is out, which will take us 19h and 23min (I've got the extended version of the first two movies), not including toilet breaks :P.

Oh dear, without HP my life would have been so boring! :D

- went to the Wizarding World of Harry Potter
- pretend to use magic
- wrote my own ending to OotP
- Got Harrys wand