Shakespeare (the programming language), the invisible programming language, programming in 282 different languages at the same time, and the programmer’s Fizz Buzz challenge.
Whitespace is a computer programming language made entirely out of invisible characters: spaces, tabs, and line breaks.

Shakespeare is a programming language designed to look like a Shakespearean play.
A polyglot programme can run in multiple different languages. One example works in 282 of them.
At a programming job interview, you may be asked to Fizz Buzz.