I saw a good quote from Mark Twain on a bulletin board at the gym the other day that makes a great birthday mantra!
Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did do. So throw off the bowlines. Sail away from the safe harbor. Catch the trade winds in your sails. Explore. Dream. Discover.
I'm off to explore and discover (my cake)! :)