I recently needed to delete a user from SQL, but the user owned a schema in each database; and the server had about 25 databases. It wouldn't let me just delete the user from the Security node, I had to go into each db and delete the schema and then delete the user. After I had done about three of these I remembered an undocumented stored procedure that lets you write code that will execute in each db, one at a time.
It's not groundbreading code; but it's cool to have an example of to do some quick maintenance, so... here it is