Sorrow: I can confirm that most of the Bad Gateway errors are due to a series of DDOS attacks (Distributed Denial Of Service). If you don't know what that means, imagine you're about to walk through the door into your favourite restaurant when suddenly 500 people push in line ahead of you. You can't get in until the crowd is cleared. Essentially that's what's happening to the forums, with the restaurant being the server, and you and the crowd being your computer and other computers. Someone is hijacking other computers to send so much traffic to our servers that legit traffic can't get through.
We're doing what we can to mitigate these attacks, including tightening server-side security and allocating more resources to the servers so they can handle more traffic. We're also working with our host to increase DDOS protection on their end.
IMPORTANTLY, NO USER DATA HAS BEEN COMPROMISED. A DDOS is people standing around the door to the server, NOT people getting in.
We thank you for your patience and understanding during this situation. We know it's been frustrating and we're working hard behind the scenes to get everything working properly as soon as possible!
... and the Gateway's open. 
What's your call, Tarot? ... Sabrina? Anybody? sigh........ 
