Hobbit Day, celebrated by fans of J.R.R. Tolkien's books about middle earth worldwide, is scheduled to fall on Bilbo and Frodo Baggins' mutual birthday, the date of the Long Awaited Party (translated in text by Tolkien as September 22).
In large part, Hobbit Day is usually taken up with the fun activities, feasts, games, costume events, fireworks and the like. Hobbit Day is a virtually ideal holiday, incorporating attractive elements of several others: the masquerade fun of Halloween, the feast of Thanksgiving, the exchange of greeting cards and gifts associated with Christmas and birthdays, the picnic atmosphere of Labor Day and Memorial Day, the fireworks of Independence Day (or Guy Fawkes Day)... and the study and reflection associated with many commemorative days throughout the year.
Coincidentally, September 22 is also Dear Diary Day this year. Honor the (fictional) memories of Bilbo and Frodo (who were quite prolific diarists in their own rights) by writing down the story of your life's adventures.