Remember this post and the followup post here for creating cheat sheets? Well, Brett has done an amazing job taking a hack solution and turning it into something gorgeous. Please, go download it and revel in it's perfection.
For the record, I don't consider it a "ripoff" as Brett describes. It's an evolution by someone better than me. That's awesome.
There are only a couple dozen people in the world doing truly original work. I'm guessing most of them are mathematicians.