Gameservers wrote that they "pushed some upgrades through to help prevent sites getting hacked." From what I can figure, there were two problems as a result...
(1) Everyone with a standard SMF installation had their forums go down because GS messed with the file permissions that SMF requires (this explains the forums being down in the early afternoon, but HLstatsX still working)
(2) Our particular webserver had additional issues with the upgrades (explains why everything went down from evening to midnight, including stats and FTP access.)
There was quite a bit of complaining in the GS IRC channel last night.
I really wish they'd be more transparent about their "updates" though. They've broken our forums and databases several times before with random, unannounced changes...