Haidhausen is a district of Munich, where the Kultfabrik and Ostbahnhof can be found.
To get there, take any S-Bahn or the U5 and get off at the Ostbahnhof train station. If you want to go to Kultfabrik/Optimolwerke either follow the signs, or the stream of teenagers.
There is a Nachtkantine where you can eat, and stands selling kebabs (Döner in German) and the like.
This place is a 60,000 square-metre entertainment mecca. After Europe's largest disco complex - located in the terminal buildings of the former munich airport - had to close in 1996, the city had to find a replacement for the crowds of partygoers. It was called Kunstpark Ost (KPO) because of its location in a former industrial complex near the eastern railway station. Rumors about closing this area too started soon and according to the bills of its clubs and bars it should have been closed at least four times a year. In 2003 it looked as if the days of the KPO are really counted, so some of the clubs moved to an area 200m in the west called Optimolwerke. However most clubs on the original area (renamed to Kultfabrik) remained open and as always a few weeks later noone talked about closing it any more.
So Kultfabrik and Optimolwerke (and two more discos on the west end of the whole area) really are one big complex and most people do not distinguish weather they go to Kultfabrik, Optimolwerke, Kunstpark Ost or the "KPO" (pronounced like the English letters!). To have so many discos and clubs on a relatively small area is brilliant, because there is something for (nearly) every taste. And if you don't get into one, there is always another. But be warned that most of them may not be what you might expect from a big city like Munich. There are many visitors from outside munich who just took off their "Lederhosn" two hours ago and got in a pair of jeans to spend a night in the big town. And few of them are over 25 years old. It does not get really full before about midnight or later, but if you come earlier you are more likely to get cheaper/free entry.