Microsoft has released SQL Server 2008 R2 RTM Cumulative Update 10. This is Build 10.50.1807.0, and it has 13 listed fixes. You must have SQL Server 2008 R2 installed before you can install this Cumulative Update.
As always, I want to remind everyone that this update is only for SQL Server 2008 R2 (which is a separate major release from SQL Server 2008).
Especially since Microsoft added some new functionality (such as some new DMVs) to SQL Server 2008 R2 SP1, you really should be making your plans to get on the SQL Server 2008 R2 SP1 branch, instead of staying on the RTM release branch.