Well,
With the current Unit that I'm posted with the CO and the RSM send out a Birthday card to all personnel, military or civ, having a Brithday. The card consists of the Branch Crest on the front and a message inside that reads: "On behalf of all members of the Branch, please accept our congratulations and best wishes upon the occasion of your Birthday". It is personally signed by both of them.
Now, within my section (we are located in our own building), I get a Birthday cake each time one of our pers civ/mil is celebrating a Birthday, we also pick up a card which circulates in a file folder around to get everyone's signatures on it. We eat the cake in the canteen. (I eat most of the cake!!). We also prurchase a small something or other for every pers who leaves our section for another one, or who is posted/transferred out.
It's a morale thing and it does wonders. I never get a Birthday cake at work...I always take the day (and the day after) off to recuperate!!