Bilbo's Farewell Party
Bilbo Baggins departed from the Shire on his 111st birthday, which was coincidentally the 33rd birthday of his nephew Frodo Baggins. The "Long Expected Party" was a huge and expensive celebration attended by most hobbits in the area, but a portion of the party was "invitation only" with 144 guests. The party included copious amounts of food and drink, and Gandalf the Grey provided fireworks for entertainment.
The occasion was notable in Hobbiton for Bilbo's abrupt disappearance (he used the Ring to disappear at the end of his birthday speech), but the most historically important event was Bilbo leaving the Ring in Frodo's keeping when he departed.