I found this while trying to get a closer look at the house in the logo.
- Open a browser window to http://diy.stackexchange.com
- Zoom in until there's a horizontal scrollbar displayed.
- Scroll to the right.
This occurs in both Firefox 3.6.14 and Chrome 9.0.597.107 on Linux (Fedora 14). Also IE 8.0.6001.18702, Firefox 3.6.14 and Chrome 9.0.597.107 on Windows XP SP3.