Mark Nottingham does a lot of good work.

This isn’t as important, but quite fun: Emulating W3C ,tools with mod_rewrite – a series of mod_rewrite rules for making it more convenient to be able to validate your pages and so on. I’ve added the rules to the .htaccess for this blog, so that visiting http://philwilson.org/blog/index.html,validate should show you whether my blog validates or not.