Yuletide is one of the seasons often used by the GM to release a new winter-themed adventure, sometimes a limited-time scenario, sometimes permanent.
2004[]
Quest:A Cold Winter's Night was released around Christmas this year, as a permanent quest.
2005[]
Quest:The Beast of Ironfang was released as the winter scenario of 2005, as a permanent quest
2006[]
There was not any particularly winter-themed adventure added at Yuletide this year
2007[]
Not one, but three winter-themed adventures: The Killing Hand of Winter, The Ring of Black Stones and Rise of the Frost Demon, all permanent
Also, And to All a Good Night, temporary
2008[]
A Blizzard in the Hills was initially added as a limited-time scenario, but it was later brought again as a permanent adventure.
2009[]
The winter event of 2009 was The Obelisk of Winter, temporary.
2010[]
The Yuletide event of 2010 was The Great Palobread Man Roundup, temporary
2011[]
There was a short event we've called Yuletide 2011
The Yuletide quest for 2011 is a trip to Snow Island, available from Friday (12/30) from Zumryn's Battlegrounds