At night...

So when the game is over and your next train is not before 7am the next day, the best thing to do is to discover Germany by night. And the good news is that you find caipirinhas everywhere.

And if you think it could be better, you can always set up your own band with friends to roam the town. Meet 'Feijoada Completa': the band which brought samba to the streets of industrial Dortmund (people actually thought we were really from Brasil and we were even interviewed by German TV).
I love how late night is special wherever you go. You meet the weirdest people at the most unexpected places.
You can even meet people from beyond the grave (Karajan in this case)