Birthday: Look Who Else's Birthday is September 22nd

In the Lord of the Rings, in the first chapter, "A Long-Expected Party", both Bilbo and Frodo Baggins celebrate their birthday on September 22nd, 3001.

Here is a summary and commentary of that chapter on tor.com.

So as tor recommends

So my dear Bagginses, Boffins, Tooks, Brandybucks, Grubbs, Chubbs, Burrowses, Hornblowers, Bogers, Bracegirdles, Goodbodies, Brockhouses, Proudfoots (Proudfeet!), and even Sackville-Bagginses—I encourage you all to celebrate in the finest hobbit tradition: drinking ... (root beer), eating good food, and sharing in the company of your friends.