Possible Skin Celebration idea

I openly admit to playing League of Legends more than most games I own. However, I still occasionally look around and see what other games are up to. This event that Infinite Crisis (a game that's basically League but with DC superheroes) is doing is having all "skins" available to use for one week. It made me wonder if it would be possible for League to have something like this occur sometime even if it was to a smaller degree.

Feel free to comment and respond :)