Mine is April 15th. I have an unusual ritual for it.
The first thing I do with the day is accomplish anything I've been putting off. Any appointments or calls I have to make, any to-do lists, anything I have to mail. I face anything that's been nagging at me. It's the one day a year that I absolutely do not accept the word "no" in my reasoning -- unless it'll improve my life -- regardless of how many tricks my brain tries to play on me. Then, for the rest of the day, I do my best to feel good about myself and how far I've come along in general. It's really like a celebration of how important it is for me to fight for happiness in my life.
It'll be three years next April. It's kind of silly, but I really enjoy the custom I've developed for that time.