The Hello World collection
Every time you write you start learning a new computer language, one of the first examples you come across is the “Hello world” program: a demonstration of possibly the simplest thing the language can do — to output the message “Hello, world!”. This has become such a cliché that this example is given even in languages for which outputting messages isn’t a core strength, or even when the example doesn’t teach you much.
Since 1994 Wolfram Rösler has been collecting all the examples he’s come across. The result is a victory of human endeavour over common sense. But it demonstrates, if nothing else, the sheer (and ridiculous) variety of programming languages out there.
If you want to see examples in more common languages take a look at those for VisualBasic.NET and Java. For low level languages take a look at 6502 assembler and ZX81 assembler. For an insight into people with far too much time on their hands I recommend the examples in Ook, Whitespace, Brainfuck and Piet.