There has been a Mega-Bahnstreik (mega rail strike) by the Lokführergewerkschaft GDL (train-driver's union) which was to have lasted from Wednesday 5th November until Monday 10th. The Wednesday was freight trains only, but the other days affected passengers on Deutsch-Bahn RE and S-Bahn trains as well.
Thankfully the strike ended 6pm Saturday, so the commemorations for the 25th anniversary of the fall of the Berlin Wall weren't affected too much. A bit of an irony there; that one of the main complaints from former East Germans about the fall of the Wall is that it exposed them to exactly the same market forces that have forced the train-drivers union to strike in the face of privatisation of the railways.
Anyway, if you are faced with long delays getting around on the Berlin rail network, one solution to pass your time is to read a good book. I spotted this paperback-book vending machine on the platform of the U8 at Alexanderplatz which would fit your needs perfectly! What a great idea!