I've installed the xajax library for PHP. It's part of my nefarious plan to play around with Ajax outside of the Google Maps API. Unfortunately, I don't really have any forms that need dynamic validation right now. Maybe I can make one up. I've also been looking at unit testing frameworks for PHP.

ETA: I was curious as to what Wordpress would do if I posted an entry without a title; it merely uses the post's database ID as the post slug. I wasn't really expecting failure, but neither did I expect something so prosaic. I've changed it now...