mimeTex
{$ x=\frac{-b\pm\sqrt{b^2-4ac}}{2a} $}
I decided I wanted to have the same functionality found in Google Docs on my site, and not have to make equations there and move them to my server and embed them as images. So I did some digging and found mimeTex, and and a simple recipe for wrapping the cgi into PmWiki for use there.
I like it.