Yuletide is a popular annual rare-fandoms gift exchange fan fiction challenge, encompassing gen, het, femslash, and slash. The idea of Yuletide is to provide fiction for people who may never have seen any stories for a source they love, or have seen so few that they’re starving for them.
Importing the Yuletide Archive to the Archive Of Our Own had been planned for a number of years. While the challenge has been operating on the AO3 since 2009, it was not until May 2014 that we were able to actually move the original archive for the years 2003 to 2008.
Read (or edit!) the Yuletide article on Fanlore.