Long Night of the Museums

The Long Night of the Museums is a twice-yearly event held in winter and summer where many of Berlin's museums open until late in the night - until midnight or later - with special programmes and events. A €12 ticket gets you entry to all participating museums as well as free use of the seven shuttle bus routes connecting the various locations.

There is a website: http://www.lange-nacht-der-museen.de/, but in German only. The full programme may not be online until a month or so before the Lange Nacht in question, but often a PDF file is available as a preview (this too German only), look for the link "Programmheft als pdf-Version".