Blood can be donated at the Red Cross in Oberursel on Friday, 14th July 2017 between 3.30pm and 8pm. The Red Cross is located at Marxstraße 28, opposite the U-Bahn station “Lahnstraße”.
To donate you must be healthy and between 18 and 68 years of age. If you have not donated before, then you must not be over 60. You must take some form of identification with you, such as a passport, that contains a photo.
You can read more about what then happens here (in German).