According to the WoW-Europe forums, we're going to have an extended downtime on August 30th to update the server hardware for Thunderhorn. I assume this is the long-promised hardware update from earlier this year and I hope it alleviates the spiky lags and other issues we experience from time to time on Thunderhorn.
On the negative side, the downtime means no WoW possibly for you. It's not just Thunderhorn getting upgraded. There must be about 30 realms listed in Group 2. Ladies and gentlemen, start your Guild Wars. (-: