As promised and as per tradition, id Software has released the Doom 3 source code under a general public license — GPL3, to be exact — for programming aficionados to study, tweak, and otherwise have a great holiday glued to their respective displays. No game data is contained, as it's of course still covered under EULA, and the original engine's shadow rendering trick known as Carmack's reverse has been replaced for legal reasons. Speaking of Carmack, the id cofounder and legendary codesmith took to Twitter to thank software programmer Timothee "TTimo" Besset, who "did most of the work of getting it ready for release." We suggest you thank him, as well. Tell your computer science-incilned friends to alt+tab out of Skyrim and enjoy!