It is really interesting that anything can be celebrated. These can include areas of physical, spiritual, emotional and mental. A new beginning in any of these areas can considered a birthday: you are giving birth to a new habit or way of life which allows you the opportunity be a better, more complete individual. Try to pick a plan or idea which enables you to do this. The change needn’t be huge. The book ‘One Small Step Can Change Your Life (by Robert Maurer, Ph.D.) emphasizes making small, realistic steps (such as walking five minutes daily for exercise).