If you know of more downtimes, either announced in the developer news, or unexpected, please, post it following the chronological order. If you add time stamps, add the timezone or keep them at CET for uniformity.
2006-11-13 : Downtime announced for nov 13th & 14th, to move the game to new, more powerful servers. Expected downtime is from nov, 13th (09:00am CET) to nov, 14th (23:00 CET), but end time might vary, depending on how the transport goes (can be shorter or longer).
2008-09-01, approx. 9:15 PM - 2008-09-02, approx. 00:20 AM CET: Popmundo down again, supposedly more updating of said server is happening right now. Is this showgeddon?