According to wikipedia, "when communicating via HTTP, a server is required to respond to a request, such as a web browser's request for a web page, with a numeric response code and an optional, mandatory, or disallowed (based upon the status code) message. In the code 404, the first digit indicates a client error, such as a mistyped Uniform Resource Locator (URL). The following two digits indicate the specific error encountered. HTTP's use of three-digit codes is similar to the use of such codes in earlier protocols such as FTP and NNTP."
That's the techspeak, but most of us recognise the 404 page as the result of an annoying broken link or a mistyped URL - something that nine times out of ten is incredibly annoying.
But that's not the case with these clever, inventive beauties. Turning a negative into a positive, it's almost worth getting things wrong to get one of these to pop up.
Take a look at our favourite 11 in the gallery below.
The Liberal Democrats
As this gallery will pay testament to, if there's one thing the Lib Dems are good at (and it doesn't appear to be winning seats any more), it's putting up absolute zingers of 404 pages within seconds of their political opponents suffering mishaps.
Witness this quick-as-a-flash reaction to Jeremy Corbyn's #traingate - was the train packed? Were there any spare seats? Who really cares? Whatever the answers, this is a pretty smart way to get a quick dig in.
The Financial Times: not exactly the number one place you'd look on the internet for 'a bit of banter' but they've got in on the act with this brilliantly nerdy/clever list of economic theories as to why the page you were looking for is missing.
A brilliant Jurassic Park themed game from a web design company in Bristol. Just remember to say the magic word.
A very simple page with an always funny video of a goat screaming like a human. It's everything you want in an error page.
Ever felt like smashing your computer and then tearing yourself limb-by-limb when you incorrectly input a url? Bloomberg knows how you're feeling. So they created this brilliant 404 animation.
The Liberal Democrats (again)
As stated, they might have suffered a bruising time at the last election, but it hasn't affected the Lib Dems' ability to bring out an online error page gag, as evidenced by this speedy response to Theresa May gaining the leadership of the Conservatives - and thus becoming Prime Minister - without an election.
Blue Fountain Media
An error page that must surely be better than the actual website because it's a game of Pacman. A risky strategy.
A simple page with that trademark Lego humour. The pirate is livid.
Hot Dot Production
A beautifully designed page that lets you manipulate the dots into different shapes. Addictive.
The Liberal Democrats (again)
Taking advantage of David Cameron’s football gaffe on during the last election when he confused Aston Villa, the team he ‘supports’, with West Ham, Nick Clegg’s rapier-witted party adjusted their 404 page in lightening quick speed, providing the below jibe on broken web links. Didn't do them too much good on polling day though.
The Rolling Stones
Can't find the page you were looking for? Don't worry, even Mick and Keith can't always get their Satisfaction.
In these post-Tinder times, this actually makes us feel nostalgic for the old days of dating. You can imagine an actual advert like this being quite successful with the geek community though even now.
A religious equivalent of the Financial Times' 404, this is probably the only error page on the internet that makes you question the meaning of life. Praise be for that.