I just got a message from our hoster. Due to internal maintainance (during which they increase our disk space for free - yay!) they need to shutdown and reboot our virtual server.
The downtime will happen some time between 23:00 CEST on the first of August and 9:00 CEST on the following day. That's between 16:00 and 2:00 CST on the same days for you american people unless I screwed up the timezone conversion. Last time the downtime lasted one hour.
Affected services are the homepage and forum, the GG2 lobby server and our TF2 community server (though I don't think anyone would notice that one anyway.) The forums and lobby will come back up automatically on reboot, I'll start the TF2 server by hand later on monday.