lol, Sorry not going to happen for most of us are not interested in sharing snaps but I have to say this one was a unique idea and may be a fun idea too if we all really celebrated it. For me it's Diwali season.
Changing banner is not as easy as changing your signature. When a theme is changed many of the codes of the forum had to be change and it's time consuming. Unfortunately even when we have some themes ready the admins have been real busy in RL and otherwise so it's not possible to change it that frequently. Besides everytime a theme is changed we get the same amount of complaints as we get suggestions to change it. So in the end it only works as demotivational for the people who work on it. e.g.
Like the snow fall we had used a couple of years ago...