I love to see a great 404 page when things go wrong. The twitter fail whale has become a great example of how to make a statement on an error or 404 page. It has become an art of both design and communication when you do something like a 404 page.
Here is a great list of interesting and great 404 error pages.
http://www.hongkiat.com/60-really-cool-and-creative-error-404-pages/
The fact that the Huffington post wrote an article on this topic means that the common non-technical person also understands what a 404 (page not found) error is. Or at least they know what it means to them
http://www.huffingtonpost.com/2010/02/11/best-404-error-pages-ever_n_456767.html
Unfortunately I’m not that up on design and will have to update jimiz.net 404 error page.