This is the second Winter Bash, we had one last year too: See http://stackexchange.com/promos/12/winter-bashhttps://stackexchange.com/promos/12/winter-bash and winterbash-2012.
Other promotionspromotions in the past were limited to one site or were marketing promotions for 3rd parties.
You can already adjust the hat position. Select a hat, then use your mouse to adjust the position just right: