When I worked in an office they got tired of all the birthday stuff so they started giving everyone the day off for their birthday. But then some people would float that to a Friday or Monday so that they could have an extended weekend. Others carried it to Thanksgiving or Christmas or whatever. It completely lost it's function along the way.
My husband's office is a nice, close bunch of people that all get along well. But they have more parties than I've ever seen. They do the cake and cards in the office and then they also go out to lunch, with my husband (the boss) paying for the birthday person's lunch. He always buys them a gift, too. This can easily add up to $40-$45. I've pointed out that this seems a little out of line. But he likes to show he appreciates them and they do something similar for him on his birthday. He thinks it's worth it in "good will".
They were getting out of control at Christmas, too. But the last few years they cut way back on gifts to others in the office and instead have a "giving tree" where you can buy gifts for needy families or developmentally disabled adults. That seems to be a much better idea.