Friends and Colleagues
It is common practice in Germany to meet with friends and family at the weekends (for instance to have coffee and cakes), or to meet in the evenings in a bar or restaurant. If you start a new job you can invite your new colleagues to what is called an "Einstand". This is a party held normally at work after the working day is over ("nach Feierabend"). The best thing to do is ask the colleagues what is the normal procedure at your new place of work. Many people also invite their colleagues to have a drink on their birthday.