I'm 21, a guy, single, never been divorced nor had kids, but maybe:
1) Get blasted
2) Forget how blasted you are, try getting more blasted, end up getting too blasted (and all that it entails)
3) Like someone above said, get laid. Always brightens up your day/week/month/life. Without getting into too much debate, as a woman, you should generally have an easier time than most men do at any relevant age.
4) Shoot guns to ring in your birthday. I'm 100% serious. It's been scientifically proven to release all those great chemicals that come with a great workout, eating amazing food, etc. and it's absolutely thrilling. I'm not asking for a gun debate either, it's just an idea.
5) Could tie in with 1 or 2, but try a new kind of food/alcohol/drink of any kind as part of turning a new chapter in your life.