Excel: Because it's there!

What do I hope to learn in Excel? Thanks to classes in high school, I already know the general operation and how to do much with this particular tool, if nothing else, this will help me reaffirm the knowledge that I already have. Aside from that, I hope to learn more about the more advanced math functions in Excel, to do more than simple add up a column or to average a few rows. Also the version of Excel that I used was 2003, and I look forward to learning about the general operation of 2007. Short of that, nothing else immediately comes to mind that I know I don't know.