December 15 is my un-birthday. It isn't my half birthday, but a completely fake birthday. When I was young my parents managed to get a fake birth certificate for me saying I was born December 15, 1970 -- exactly one month earlier than my actual birthday. The reason for this was to get me into kindergarten rather than having me wait another year. For years I had to celebrate my birthday in school by bringing cupcakes on December 15. My birthday parties were around December 15 and I only celebrated my real birthday with my family. At some point the whole thing just went away. I think it was when we moved when I was in 5th grade. Every year the date December 15 stands out in my mind whenever I hear it until I remember, as I just did, that it is my un-birthday.
Right now, I could go for a cupcake. Yellow cake, buttercream frosting, and a candle. And maybe 20 5 year-olds singing happy birthday.