My colleague Steve emailed me today and asked "why are there 214 indices on the table SA_OrderHeader?"
I laughed, and told him don't be silly. SQL Server Enterprise Studio showed 'only' 22. But Steve was using SQL Manager 2008 for SQL Server and saw the strangely named indices below:

Intrigued, I did an sp_help SA_OrderHeader and now I could see them...hypothetical indices!

So, I did some reading about this, and it turns out these are created by the Index Tuning Wizard, and are normally removed when it runs to completion, but I guess sometimes not... see here for instance....