Microsoft has released SQL Server 2012 Service Pack 1 Cumulative Update 1, which is Build 11.0.3321. I count 44 fixes in this Cumulative Update.
You will need SQL Server 2012 Service Pack 1 installed before you install this Cumulative Update. If you already have SQL Server 2012 installed, you only need the actual Service Pack itself. You don’t want the full FullSlipstream installation that is also listed on that same page.
If you are getting ready to deploy SQL Server 2012 (or even if you already have it deployed), you really should be on the SP1 branch. I also think that you should be on SP1 CU1, so that you are completely up-to-date with all of the released fixes. Microsoft continues to fix lots of issues in each of these early cumulative updates for SQL Server 2012, so I think it is more important than usual to stay current.