congypsy.com until recently had a single validation error (XHTML 1.0 strict), and I can’t stand for that sort of thing on a site I work on. The source was the “Latest updates on Twitter” section; I was using Twitter’s pregenerated code bits with just a little modification, and their script expects the <ul> it uses to have a particular ID. The problem came in when I had two of them on a page; obviously, you can’t have two objects with the same ID on one page! But to my surprise, everything worked as expected in Firefox, so I left it alone for a while. (Fail)

So then I realized I could just download the script from the Twitter site, modify it slightly, and free myself from the horror of invalid XHTML. UnFail.