The Viennese love music.  If the music was written by Mozart or anyone from the Strauss family, that's a bonus.  Walk down any street in Vienna and you will be offered tickets at reasonable prices to tonight's concert (there are dozens of them hapening more or less simultaneously).  Can't make it tonight?  How about tomorrow?
We opted for a concert at the Stadtpark Wien because it was "all Strauss".  After a while I get bored with Mozart, but with the Strauss family... never.