If you need to enable SQL CLR and can't get at the Surface area configuration tool.

EXEC sp_configure 'clr enabled', 1;RECONFIGURE WITH OVERRIDE;GO

Simple really. Of course you will need permissions or else you get

Msg 15247, Level 16, State 1, Procedure sp_configure, Line 94
User does not have permission to perform this action.
Msg 5812, Level 14, State 1, Line 3
You do not have permission to run the RECONFIGURE statement.