I need to travel again... explaining the concept of 'sleazy bars' evokes too many interesting places from the dark corners of my friends' memories. And of the cities they come from.
Airport, Am Dobben 70, Bremen. Opens at 11 at night. Beware, they already close around 5 am during the week, but in the weekends you can be surprised by how light it actually is when you get out, even in the winter. And the fresh air...!
Other places in Bremen on their way, once the memory of my friend is restored sufficiently to allow others to actually try and find the place. ("It's somewhere on a crossroads.")