Just an hour ago a lot of (official) Ubuntu websites and main repositories went down for what seems to be a (large) maintenance operation. As soon as more information will become available I’ll update this post.Update #1:Hours have passed but still Ubuntu websites and the Ubuntuforums servers are down. On #ubuntuforums at irc.freenode.net various reasons are being mentioned concerning the sudden disappearance:– Major problems with servers / server software.- Compromization / DDos attack.- Power outage at Canonical, which seems to host the Ubuntuforums.As far as known there weren’t any maintenance schedules announced for this weekend. So it safe to assume that it’s a worst case scenario which is taking place. More information (hopefully good) will follow.Update #2:Channel Ubuntu (#ubuntu) over at irc.freenode.net (IRC) posted a link which holds a cached Google version of https://wiki.ubuntu.com/archiveThere you will be able to choose from hundreds of mirrors to download packages and CD-images from if necessary.Update #3:Some Ubuntu websites are (coming) back online. The same goes for the main repositories which were also offline.Update #4:Ubuntuforums are back online.