As I wrote on the page Kirin tidings, the day of the “Juuni kokuki” special event is being held on the official site, from Dec/12 @12:00 to Dec/25 @20:00.
When I visited there on Dec/12, the page response was very slow probably because a lot of access. Now, you can see the page easily.
From the page, they say you can get an illustration for a cell-phone wallpaper or a postcard. It is a portrait of the two, Yōko(陽子) and Rakushun(楽俊), by Yamada Akihiro and available for a limited time until 2012/12/25 @20:00. Don’t miss it.