Doom 3 Source Code About To Be Made Public

Fans of 2004's hit horror sci-fi shooter Doom 3, are about to receive a nice gift courtesy of its creator, John Carmack. He's putting the source code out there for anyone to have, as he tweeted here:

doom 3 source is packaged and tested, we are waiting on final lawyer clearance for release.
This should see some excellent spin-offs and mods from the talented modding crews out there. For those that just want to play the game and not mess around with compiling it first from the source code, it's now available very cheaply from most games outlets.