On Friday, February 24th, the AdWords system will be unavailable from approximately 8 p.m. to 12 a.m. PST due to system maintenance. While you won't be able to log into your accounts during this short downtime, your campaigns will continue to run as usual. We apologize for any inconvenience.
Update: System maintenance will take place from 8 p.m. to 12 a.m., not 12 p.m. :)