Open Thread: How are you using Excel?

Yesterday, I mentioned I’d been talking with someone who’s looking at interesting things people are doing with Microsoft Excel. I talked to her again yesterday, and with her official okey-dokey, I’ll virtually introduce Tralee Pearce (*waves*), a reporter from Toronto’s Globe & Mail whom you might remember from a very swell article about the Hipster PDA.

So, by request – and to help Tralee with fleshing out her fun-sounding article – I hope you all will jump in here: What kind of cool, novel, and non-obvious stuff are you doing with Excel? What’s the wildest, most obsessive, most nerdy thing you ever saw someone do with our favorite spreadsheet program?