Duke Nukem 3D
The source code to the Duke Nukem 3D v1.5 executable, which uses the Build engine, was released as free software under the GPL on April 1, 2003. The artwork remains copyright protected. Many programmers altered so that it can be played on modern computers. As of 2007, these projects gave the game a second life in multiplayer games through the Internet and a growing community is still actively playing.