Cheers for the heads up - always better to know in advance rather than just getting a blank screen and wondering if the site's gone for good. I've been burned by that before on other forums, assume the worst and then it turns out they were just doing maintenance.
Is there any chance you could confirm roughly how long it'll be down? Even a ballpark would help. I've got a few threads I want to follow up on this weekend, particularly the one about the Rendlesham Forest evidence comparison someone started recently, so I'll just make sure I do that before the window hits.
Hopefully everything comes back running a bit smoother after. Sites like this are hard to replace honestly - the quality of discussion here is genuinely better than most places I've tried.