Its a 57 year tradition in Seattle, it starts Dec 1st and runs through the 23rd, its the Christmases cruise or the xmas boats or whatever you and yours like to call it. Run in conjunction with Seattle Parks and Recreation the event is organized by Argosy and called the Christmas Ship these days. You can find out more information about riding the Christmas Ship or being one of the Parade Ships, check out the Argosy site.