Tonight's pre conference meetup May 2011
You can find the location on the Visitor Info Map. The closest subway/S-Bahn station is called “S+U Jannowitzbrücke”. You need to go through the entrance of this house.
If you have an Android phone or any other flash enabled device, you can have a look at the street view of the entrance here.
Instructions: This is how it looks like from the outside. You go inside the entrance into the second backyard. On the left side of the second backyard there is another passage. Take the first door right at the beginning of the passage and you’re here.