I apologize to everyone for our downtime.
At approximately 4am, some form of script was ran on the server. The script managed to cause Apache (what delivers you the HTML) to crash, restart, and crash again. Each time Apache crashes, it creates a dump file. In a matter of minutes, my server's disk space was full.
PHP and PHP-based applications require some disk space to operate correctly. PHP was somehow corrupt - not sure if this is due to it unexpectedly running out of swap space, cache, or what. But it has been upgraded and repaired.
In addition, SMF (the technology of the website), uses a caching based system. When the disk space ran out, quickly and out of nowhere, it created a cache file but only partially as it ran out of space. So, Apache and PHP would try to parse the broken cache file, and thus you got the "500: Internal Server Error" message.
I will be conducting an investigation of what script was executed, how it broke things, and who did it. This most likely was not an accident. I also have reason to believe the culprit is a member of either Draconity.org or Gulf Coast Furs. If I find the person responsible, I intend to press charges as Denial of Service attacks are illegal. If you have any information that may be helpful, it would be greatly appreciated!
Also note that no security was circumvented and no data appears to be lost or stolen. Everyone's still safe and secure - it was just website downtime.