Democoding is the art and science of making programs that push the limits of what a computer can do and what the human mind can comprehend. Usually involving elements of programming, graphics manipulation and music, democoding began in the prehistoric time of the amiga computer. Authors of software cracks would leave a small effect as a signature. These effects were generally 1024 bytes of assembler code or less. Some of the most commonly used effects were fire and plasma.
As time progressed and Moore's law took its course, democoding blossummed. Demos today often use 3d accelerators and have mind-blowing effects like realtime ray-tracing. They range from "oldskool" 4k productions, which rarely have music, to 64k intros (my favorite genre,) to full demos with sizes ranging from a few hundred kilobytes to more than 10 megs.
Now primarily active in Europe, the demoscene as it is called, holds "demoparties" where hundreds or thousands of enthusiasts come togeather for days on end. Groups bring their demos and enter them in competitions for money.
Some of my favorite demos/intros are:
moral hard candy by blasphemy 3.8 megs demo
burra! by aardbei 64k intro
some bookprint and a broken heart by replay 40k intro
some other good sites for info and downloads are:
www.scene.org - biggest archive
www.demoscene.org - news
www.ojuice.net - everything
www.calodox.org/demoo - demo review and download
www.flipcode.com - demo and game programming
the wild world of democoding awaits