The SE network is about to put its silly hat(s) on again, and allow *.SE sites to enter (or not) the Winterbash 2013.
Winter Bash is an annual event that can run on any Stack Exchange site that chooses to participate. Users earn “hats” for their gravatars by completing certain tasks (analogous to badges). Certain actions trigger the user receiving a hat, which their gravatar can “wear”. We track everyone’s progress earning hats in a leaderboard.
The moderators need to opt in or out by December 1st.