What?!? You haven't finished your Christmas shopping for your favorite geek yet? In that case, I have some updates to the 2005 Grey Matters Gift Guide:

Starting with my personal favorite, Pi-related items, ThinkGeek has reponded to those of you who think it's too cold for Pi T-shirts and Pi babydolls, by bringing us the Pi hoodie!

Of course, staying inside can also help keep you warm. However, to really get that blood circulating in the brain, I suggest playing Polarity. Imagine magnets meet Reversi (also known as Othello), and you'll start to get the idea.