The area of Saxony and eastern Thuringen has of course been largely closed to traveling until the fall of the Berlin wall and the "Einheit," the reunification of  West and East Germany.  This region offers some excellent castles largely because they have not been rebuilt yet, and so you can get a chance to see real ruins that have just had some basic maintenance done to them, instead of seeing a rebuilt castle that is hardly like the medieval version. 

Also, there are several excellent battlefields from the Thirty Years War that most could not tour before.  These are featured here as well.

As of 2013, I'm still preparing to work through this area. This will be for future trips.