Oooh, speculation time

So, this mysterious Potter More website.

Which apparently has something to do with whatever JK Rowling is working on next, and according to assorted websites, is "Breathtaking in scope" and not a new book.

Anyone got any ideas what all that is about?

Or if not ideas, rampant unconfirmed speculation? Rampant unconfirmed speculation is fun

ETA: Ooooh, nifty!. So, six days until an announcement.