Celebrate for at least a month -- and have I told you about the concept of half birthdays? Never turn down a reason to celebrate!
Ignore Curmudgeon's threat of horribilia. More likely you'll wind up with a loon in the bathtub. (Hmmm...I'll let you stew for a week or so about what that might mean. Wait a minute...stewed loon?!? Eeeeyew! Cake and icecream is much much better!)