If you're using Mozilla (or Netscape 6) to view this site, make sure you get the (Mozilla) 1.0 RC 1 download. The menu system now works correctly. There was a bug between the way the way Mark coded the menus and the way Mozilla/Netscape rendered Javascript that made things get messy. Not a problem anymore...
Of course, there are always new versions coming out, so you'll want to get whatever the newest non-nightly release is when you read this.
http://www.mozilla.org/releases/