Just liked to say that I really like Formspring 404 not found page, it’s really cool :P, see it below or try to navigate to any page that doesn’t exist.

I like also to mention this great article by Chris Coyier from CSS-Tricks that talks about 404 pages best practices. You should really read it.

Enjoy your day!

UPDATE 07/09/2011:

Keep yourself updated with brilliant 404 pages by following this blog.