I'm posting from my phone and on the road, so with little of my usual flair and panache.
If you want to ensure a Doubletree room for next year's Pantheacon, you can make a reservation as soon as this SUNDAY, 21 February. Synchronize your watches...
Edit: I know what pentaclemoon just posted; I read that too, so I called the hotel. What I reported above is what Reservations told me just now. Sorry for any confusion from the apparent contradiction--if I get better info I'll retract/correct immediately, of course!