Our inhouse system is a c# / vb.net mess and a cluster of thousands of stored procedures which are full of legacy business logic that has been introduced over the years. Some stored procedures have grown to be thousands of lines long. Most developers appear to treat the SQL code with contempt where the SQL is so poorly formatted that it's barely readable and it may as well all be on one continuous unbroken line.
DBAs have decided that they want / need to think about segmenting the data into logical partitions and separating it onto logical hardware. Part of this new world thinking plan is that maintaining any existing business logic and introducing new business logic is now banned in any stored procedure change. This has forced a mammoth refactor of both SQL code and application code which will take years to complete (if it ever gets there).
Lessons in how to morph and mutate code into an unmaintainable monster.