Today is Father's Day (Vatertag, Männertag, or Herrentag) in Germany. The day is dedicated to all men and is celebrated on Ascension Day each year. It is like a "boys' day out" and often includes drinking. The custom began in the Middle Ages as a procession dedicated to "Gott, den Vater" (God, our Father).
For more information, see the links below:
Etwas für den Vatertag (in English)
Father's Day and Vatertag
Germans observe Ascension Day, Father’s Day Thursday
Why you need to go “German” on this year’s Father’s Day