@grovelli-262555 A CLR Stored Procedure is a Visual Studio.Net assembly that can be included into a SQL Server 2005+ database and its methods used as stored procedures, functions, and triggers. It is in effect a replacement for extended stored procedures, as it allows the database to call external code but in a tightly managed architecture. So if you had the need to do say file access, very complex maths or string manipulation for example, you could write the code in C# or VB.Net and call this as a stored procedure. Obviously you should only use these when they are appropriate but they are very useful in certain situations.
This is a good starting point if you want to read up on these: http://blog.sqlauthority.com/2008/10/19/sql-server-introduction-to-clr-simple-example-of-clr-stored-procedure/