After countless hours of development everybody is happy when pushing a website or application live. What people usually forget is to a create meaning-, helpful or at least creative “404 Error Not Found” page. This is not something developers often pay attention to but should.
Most sites have a banal message like “Not found” and essentially that’s what it is, but you can make users more happy visiting your page and weren’t successful finding the content they wanted. A 404 Page should at least contain site-wide links to be able to quickly jump to another page, or, be as popular and viral like twitter’s fail whale. Here are a couple of great examples ranging from creative to helpful to extravaganza.