Like hugi-compo? The latest competition was in 2009, and the winner generated a random ASCII-art maze with a 122-byte MS-DOS .COM file. http://www.fysnet.net/hugi/compoold.htm A 2006 competition was for Sudoku solvers; the winner was 67 bytes. And of course there's a whole demoscene with 32-byte, 64-byte, 128-byte, 256-byte, etc., categories. My dissection of a 16-byte graphics demo (the smallest!) is at http://www.canonical.org/~kragen/demo/fr-016.html.

In April some of us were playing with bootstrapping a development environment in MS-DOS from COPY CON: http://lists.canonical.org/pipermail/kragen-discuss/2011-Apr... http://lists.canonical.org/pipermail/kragen-hacks/2011-April... Dave Long put together a version where the machine code was entirely printable ASCII.

Brian Raiter wrote a lovely article a few years back on the smallest possible ELF executable, which turns out to be 45 bytes, which unfortunately has been broken by recent Linuxes: http://www.muppetlabs.com/~breadbox/software/tiny/teensy.htm...

Based on Brian's work, I wrote a self-compiling compiler for a tiny dialect of Forth: https://github.com/kragen/stoneknifeforth which is about two pages of code if you remove the comments. I also wrote a PEG compiler-compiler in JavaScript which is one page of code: https://github.com/kragen/peg-bootstrap/blob/master/peg.md --- ultimately I want to make a version that generates StoneKnifeForth code instead of JS, but I haven't gotten around to it.

I also designed a minimal CPU architecture: https://github.com/kragen/calculusvaporis but I only have software implementations for it so far, and no interesting code.

And I wrote a metacircular interpreter for Bicicleta in half a page of code, which I guess is some kind of "minimal coding example": http://lists.canonical.org/pipermail/kragen-hacks/2007-Febru...

https://github.com/kragen/screenfuls is a collection of tiny, readable programs that do interesting things.