I've just been contacted by our hosts as they're currently investigating a suspected hack attack on the forums. They've turned off the forum software temporarily while they trace the issue, so please bear with us.
More news later :o)
Update: You should now be getting a 403 error, as the site's been taken offline by the hosts to prevent it crashing the server cluster we're on. The selfish actions of one hacker is affecting several thousand websites when BM is taken down, as it crashes the whole cluster.
Keep watching this space for updates.