We will be moving to a new server tomorrow, starting around 12PM (noon) Pacific Time. This will involve some down time. The forums will go into "maintenance mode" on the current server, after which you won't be able to access the forum content. The forums and our main website will then be moved. The migration itself should take only a couple of hours, but DNS propagation may take a bit more time.
You should all be able to access the new server within 24 hours or so, at most, and for many it will be well before that. Check back regularly and when you see the forums are out of maintenance mode, you'll know you're accessing the new server.