We used to celebrate monthly birthdays, each department would pay for a cake and beverages. It got to the point where people would complain that they didn't like the chosen flavor of cake and then once someone (their birthday was that month) asked to have the date changed because she wasn't going to be in. It just got to be such a hassle, so we stopped. One year just a few of us celebrated each birthday by going out to eat, but we only did that one year. I'm actually happy to have stopped all of that celebrating anyway. Now it's just me and 2 friends that go out to eat to celebrate. Much cheaper!