In a nut shell it is a mass art trade where you are working to create a drawing, story, CGI model and other things I don't really know. (They'll say on the page) for a random user also taking part. While some one you don't know is doing it, is doing the same for you.... And the random user you are arting for is also unaware (don't tell)
I'm not taking part this year, but I can spread the word. There are only a few days to apply left so do it before the 22nd of this month o3o