I don't. I just see no reason to celebrate something that I barely had any part in, let alone it being something I didn't achieve myself. Seems just like a waste of time and money to me.
We usually celebrate by going out for dinner at a favorite restaurant. Then we come home to have cake and open gifts and hangout by playing games and such.
Usually whoever's birthday it is picks what they want for dinner. It can be nearly anything food from a restaurant, or something my mom makes. They also choose the cake. We eat dinner, do cake, and then presents.
The old gal makes me a monster meal of all my favs and any extra special treats. She makes one mean cheesecake I tell ya. I like the marble chocolate swirl kind. Those cakes have to weigh about 20 pounds because man are they heavy on the tummy. I can live on good cheesecake.