Facebook is down and has been experiencing outages since about midnight Eastern Time tonight, Oct. 5, 2010.
Many Twitter users are reporting the outage, with hundreds of tweets appearing about it in minutes. DownRightNow.com confirms the downtime, with the first widespread problems starting about 11:52 p.m. EST.
TechCrunch reported that a site redesign could be unveiled tomorrow. If true, it would come less than a month after Twitter announced its major site redesign (features for that here).