Codename of Sharepoint 2013 is released on 1 Feb 2012. According to PJ Hough (CVP of Development, MS Office Division) - Codename of Sharepoint 2013 and Office 2013 is "Office 15".
PJ Hough is also said about this release: "First time ever, we will simultaneously update our cloud services, servers, and mobile and PC clients for Office, Office 365, Exchange, SharePoint, Lync, Project and Visio".
Here are some key features of "Office 2015": It is a true 64-bit version, a truly touch-enabled Office, "Ribbon" getting replaced by "Metro" style browsing , and It need to support ARM processors(ARM is the industry's leading provider of 32-bit embedded microprocessors).
Important links for more info on Sharepoint 2013/office 2015: http://aarohblah.blogspot.com/2012/02/sharepoint-vnext.html