The Myth War Online Website details the Christmas Carnival that's coming to their virtual world on December 24. Also, the Guild Wars Support/Game Updates page outlines the most recent updates to ArenaNet's MMORPG (thanks Frans), including word on the Winterday/Wintersday festival that's getting underway:

The Wintersday Festival has arrived! Kamadan, Lion’s Arch, Droknar’s Forge, and Ascalon City are decorated for the occasion, and over the coming days, holiday activities will begin as special guests arrive to join the fun. Everything leads up to the big Winterday celebration on January 1, which will take place every three hours in Lion’s Arch and Kamadan (on the hour in Lion’s Arch and 15 minutes past the hour in Kamadan). Be sure to collect Candy Cane Shards for use in the big celebration!