In the years before recorded music, radio, movies, and television, people gathered to make their own music and drama.
Germans also formed clubs to play cards, particularly skat, a card game that originated in Germany, and pinochle (said to be brought to St. Louis by the Plattduetche Society).
Some choirs, theatrical groups, and card clubs were standalone organizations. Many others were enjoyed within a larger group such as a Turnverein, a benevolent and protective association, or people who worked in the same industry or emigrated from the same region of Germany. If you research German social groups, you are likely to find that its members formed choirs, put on plays, or had other activities that seem to go beyond its stated purpose.
Overview of German theater in St. Louis (in German):
Singing societies with records at the Missouri Historical Society include: