Text Mode Framework - A sample demo with full sources, in C++, by mu6k.
FTW7 - Moerder's console wrapper to allow fullscreen display of textmode demos in Win7.
ConsoleWrapper V0.1 - Same kind of wrapper as the above, made by Fragment.
TMDC Template - A simple demo template, in plain old C, integrating FMOD and LibCACA, with no other dependancies.
Sol's TextGL - An implementation of OpenGL in textmode, using TextFX.
Sol's Code - Home of TextFX, easy text mode graphics library, among other things.
AALib - The (in)famous ascii-art library (for linux), used to render quake in ascii art, for instance.
libcaca - Does pretty much the same as the above, except it supports color.
dosbox - DOS emulator (virtual machine). Works rather well.
qemu - Virtual CPU emulator, rather fast, and is able to run many old demos already.
Regular sponsors & other cool people
tAAt.fi - Home of tAAt ry and tAAt the demogroup, the creators of TMDC.
Rusty Axe Games - Home of Rusty Axe Games, makers of Big$hot, Real E$tate Empire, Aztheca and others.
Ixchels Studios - Home of Ixchels Studios, makers of Aztlan Dreams, Wicked Defense and Wicked Defense 2.
Secret Exit - Home of Secret Exit, makers of Zen Bound and Zen bound 2.
Scene.org - Huge demo archive