Dutch birthdays:
Even when it is nobody's birthday, you are still confronted with birthdays every day! Most Dutch people display a birthday calendar in the bathroom, so as not to forget anyone’s birthday.
People rarely send out invitations and presents are often inexpensive. Gift certificates are popular.
The invitation to a birthday party is usually for 'coffee', from 8pm to 9pm; later on drinks are served. When visiting a Dutch friend at home, it is customary to take a bunch of flowers (quite inexpensive in Holland) or some candy. A bottle of wine is also appreciated. The Dutch do not feel comfortable with people dropping in unannounced, not even on a birthday! The custom is to bring pastry for colleagues at work to enjoy over coffee. It is customary to congratulate not only the person whose birthday it is, but also their relatives. To say "Congratulations on the birthday of your brother-in-law" would be quite normal.
(Some text from rootsinholland)