id has added their back catalog to the Steam digital ditribution system, and until August 10th, there's a special deal available. You can get all of these:
Commander Keen, Episodes 1 through 5
Wolfenstein 3D
Spear of Destiny
Return to Castle Wolfenstein
Ultimate DOOM
DOOM II
Master Levels for DOOM II
Final DOOM
DOOM3
DOOM3: Resurrection of Evil
QUAKE
QUAKE Mission Pack 1: Scourge of Armagon
QUAKE Mission Pack 2: Dissolution of Eternity
QUAKE II
QUAKE II Mission Pack: The Reckoning
QUAKE II Mission Pack: Ground Zero
QUAKE III Arena
QUAKE III: Team Arena
Heretic: Shadow of the Serpent Riders
HeXen
HeXen: Deathkings of the Dark Citadel
HeXen II
For $62.95.
I was weak, I bought it.
Commander Keen, Episodes 1 through 5
Wolfenstein 3D
Spear of Destiny
Return to Castle Wolfenstein
Ultimate DOOM
DOOM II
Master Levels for DOOM II
Final DOOM
DOOM3
DOOM3: Resurrection of Evil
QUAKE
QUAKE Mission Pack 1: Scourge of Armagon
QUAKE Mission Pack 2: Dissolution of Eternity
QUAKE II
QUAKE II Mission Pack: The Reckoning
QUAKE II Mission Pack: Ground Zero
QUAKE III Arena
QUAKE III: Team Arena
Heretic: Shadow of the Serpent Riders
HeXen
HeXen: Deathkings of the Dark Citadel
HeXen II
For $62.95.
I was weak, I bought it.