I keep getting an HTTP 500 response why I try to navigate to the main site.
This only occurs when I have an active session (I'm logged in).

Support & Feedback also isn't working.

I too having same issue for the last 20 minutes. Tried from both Opera, and Firefox. From Opera I get following message, which I guess is generated by Opera browser:

The deckbox.org page isn’t working
deckbox.org is currently unable to handle this request.

I am not having an issue (Chrome). It could just be a hiccup from Sebi changing the site.

Something is indeed broken, checking now.

Back on line for me. Was out for about 30 minutes.

Should be fixed now, sorry for the problems.