Internet whimsy: I'm looking for more examples of quirky web and computing stuff, here's what I have so far

Part of my day job involves writing about computer science (in its widest sense) for the Computer Science For Fun (CS4FN) blog and print magazine(s). We write about computer science research, history of the topic, themed stuff, how to do something or other - all sorts. 

I'm also a big fan of the Really? No, Really? podcast in which the hosts (Jason Alexander and Peter Tilden) have a guest on each week to talk about something that's amazed, amused or baffled them and sometimes all three. 

There are lots of stories in the world of computing that do the same and I thought I'd write about some of them, but while I know lots (below) I'm sure there are others I've not heard of yet. 

What am I missing in the list below of quirky computer science type things? 

• Lava lamps and security - Cloudflare trains a camera on a wall of lava lamps and converts the images (incredibly random!) into a string of numbers to help with encryption.
  
  
• "Open Office can't print on Tuesdays" - a glitch which meant that if the word Tue appeared at a particular point in a line of metadata then the file was miscategorised and treated as a non-printing file. The fix was to replace all instances of 'Tue' with 'tue'.
  
  
• "Can't send email further than 500 miles" - a university stats team in North Carolina found that they could only email within a 500 mile radius. The culprit was the length of time allowed for a ping message and its response. It didn't time out when emails were sent 'locally' but the message took too long once the distance was over 500 miles so the emails failed.
  
  
• The UK Government website for Bank Holidays displays bunting if you visit it on the day of a Bank Holiday (on Christmas Day it displays tinsel).
  
  
• IP over avian carriers - an April Fool's joke written as a serious document discussing the transfer speed of data sent by pigeon. The real-world equivalent is river rafting tourism which used carrier pigeon to return camera rolls to the head office which could then be processed for guests to collect once the trip ended.
  
  
• Google's Pigeon Rank - another April Fool's joke with Google explaining that pigeons were used to pick websites to display when a user searched for information. The real-world equivalent is the discovery that pigeons are pretty good at discriminating photographs of healthy tissue samples from diseased ones.
  
  
• Broadband over wet string - this one is peak internet whimsy ;) Engineers had a go at getting a signal to transmit over wet string and managed to get an impressive 3.5 Mbps. Althugh wet string is conductive apparently it's more about the medium acting as a wave guide for the high frequency signal.
  
  
• I need to dig out the nice story on Twitter of someone's mum being paid to try and test software to destruction - she first used social engineering to get into the room and the program by carrying an awkward amount of papers and struggling through a door then simply asking people "what's today's password".
  
  
• Optical mice don't always work in bright sunshine.
  
  
• The first webcam was pointed at a coffee machine so that people could check whether there was coffee left.
  
  
• The Utah teapot as the first item rendered digitally in 3D.
  
  
• Ada Lovelace and the first dry run table.
  
  
• HTTP status codes - many fairly dull, one or two demonstrate a bit of whimsy.
  
  
• List of animals awarded human credentials (formerly 'list of cats with fraudulent diplomas') - edging out of remit but computational in the sense of logic - testing the weak points of a system where people can get PhDs without doing the work, as demonstrated by people getting qualifications for their cats and dogs. To make it a bit more computing-relevant I might add something in to this post about web certificates and keychains etc.
  
  
• "What kind of medicine does Dracula take? Con medicine" - this baffling cracker joke can be explained by jokes written in fonts with a ligature then printed on devices with fonts that don't have it, meaning that the word 'coffin' loses the ffi as ligature fonts treat that as a single glyph. Bonus material: non-English orthography and how many foreign names and addresses used to get mangled when people entered them into the old CS4FN mailing list database.
  
  
• Les Horribles Cernettes - first picture on Tim Berners-Lee's interwebs. See also Annie Rauwerda / Depth of Wikipedia's TikTok about them.
  
  
• Mark Rober's dartsboard that uses Arduinos, computer vision / motion capture, sensors and rapid trajectory calculations to ensure the dart always lands you an excellent score.
  
  
• Please add your example of computerish internet whimsy to this form :-)