I voted three ways (I had to vote in the election for the European parliament, for the city council and the district council). For the European parliament I voted for the pirate party. They might have had some fuck ups, but I still think they could manage some good things in the EU. For the district council I voted for the green party (as there were few other choices), and for the city council I voted for the PARTEI. The PARTEI (literally "the party", short for "Partei für Arbeit, Rechtsstaat, Tierschutz, Elitenförderung und basisdemokratische Initiative") is strongly linked with the satirical magazine "Titanic", and not too serious. I consider voting for the PARTEI to be a good way to show that you're unhappy with every other choice, without giving your vote to the extremists who manage to make all their peers vote. Also I feel like they could do some good things if they actually managed to get a seat.
I was strongly considering to vote for the Left party, but they had no candidates for the district council (so I couldn't vote for them), and I wasn't sure about them in the European parliament.