As I was watching videos on YouTube about the Large Hadron Collider, this series of videos called The Periodic Table of Videos caught my attention. I am sharing the video of Antimony with you (Antimony is the name of my avatar in Second Life) here:

What would the math equivalent of the periodic table be? We have sets of numbers, theorems, functions, and rules, but what interesting, unifying element (note the pun) could you build a set of videos around?