I've done blood donations in Germany - in my small hometown and in Berlin. In Berlin it was at a "donation service" associated with a big hospital, where you can donate platelets, too. In my hometown blood donations are organized by the local chapters of the Red Cross. I loved it because it had a homey feeling (a lot of people knew each other) and therefore it helped me when I started donating. I preferred donating in the next village. There the food was legendary: not only "Mettbrötchen" (rolls with minced raw pork) and other sandwiches but lots of homemade cakes :)