Open Air music performances are quite common in Munich. They’re so attractive for me. Sometimes the political parties (SPD, CSU, die Linke, etc) hold some concerts which usually attract a large number of people. Although normally there are a lot of foreign tourists at Marienplatz, but of course there are many German tourists as well.One time I really enjoyed an open air concert performed by musicians from Switzerland. It was a semi-classic music performance. The weather was great which made the atmosphere even much better. People were really glad with the show; they were clapping several times during the show, some were even shouting :) So, just keep your eyes & ears open to see & hear if there’s an open air show somewhere. I’m sure that’s worth it, especiaally when the weather is nice.