Server Maintenance: Patch 4.11 (Source)
On 02/07/2014, starting at 01:30 PST, ranked queues will be disabled in preparation for patch 4.11. At 03:00 GMT, the servers will be shut down and all games currently in progress will end in a draw and stats will not be recorded. We estimate the battlegrounds will be unavailable for 6 hours.
League of Legends : Patch 4.11, servers maintenance
Servers will be unavailable tonight. Riot Games will deploy the new 4.11 patch on the live servers.