I just got 502 a few minutes ago and also when i go to the forums i get "welcome to nginx" most of the time. I have to get onto the forums via a sub-forum and the it will work.
Hang in there guys... this has to do with the Comet Chat bar at the bottom of each page of the site. We are all trying to decide if it is worth keeping or not. From the poll results so far, it is not being used enough to justify keeping it, but I'll give it another day or two and see if we get more input.