For many years I wanted to have a once a year full day game. I participated in that sort of campaign once long ago and it was fun. I was able to recreate that a bit when I had Tenth Anniversary Game in 2003. That moved us into having an online game so that Players from around the Country could rejoin our game. Now I have decided to pick a day of the year and run a day long game.
I am calling this "BOB's Birthday Game" because the first time we will do this in 2010 will be timed for my birthday. In future years the date might move around the calendar. The goal for each year is to have some of the retired Players to return for the day to enjoy their roleplay. Some players have referred to these as Bonus Games.
Each of these games is 'in-line' with the normal campaign. The characters will continue their story arcs and I will figure out a way for visiting Players to join in logically with the story.