I've written one clr. It was a work around for being able to call an application on a backend AS400 without having access to Microsoft's OLEDB provider for DB2. That provider is only available with the Enterprise Version of SQL Server and since SQL Server is secondary in our environment, Enterprise was not an option. My clr function uses ODBC to connect to the 400 and execute a single program. The biggest pain of the whole thing was getting the proper permissions set for the stored procedure to actually run. Thank goodness for all the blogs/documentation/help on here and Microsoft to try and solve the errors I received on every step of getting it to work!