Here's the NA version of the Riot NOC post for this maintenance:
On 02/11/14, starting at 01:30 PST, ranked queues will be disabled in preparation for patch 4.2. At 03:00 PST, 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."
Looks for your particular servers status thread? Here's a collection of links: