Around Christmas, I like to pull out Santa hats for the kids. Although I tend to stay away from putting the entire family in Santa hats, I think they are really great for individual and small groups of children. They are smile makers because kids love them and they are really cheap to find and keep on hand. I have even seen them at the dollar store.
When it comes to Santa hats I love to do close ups, just far enough away to be able to see that it is a Santa hat. Pictures in Santa hats are great for Christmas cards or ornaments. Although the hats are fun, I usually only try to do a small portion of the session in them because nobody wants Santa hats on their walls all year round.