Marathon Now Totally Free
Bungie Studio's excellent series of Marathon games (the prequals to Halo) are now 100% freely available for download. Marathon 1, 2, and Marathon Infinity went open-source back in 2000, but all the music, art, and maps were not legal to download. Now you can download all of it. And thanks to Aleph One you can play them on Mac OS X, in OpenGL, and with better networking.
"Marathon, Marathon 2, and Marathon Infinity are now all available free of charge. Marathon 2 and Marathon Infinity are fully compatible with Aleph One; just replace the Marathon 2 or Infinity application with the Aleph One application, and enjoy the benefits of OpenGL graphics, improved networking, and everything else that has been added to the game engine since it went open-source in 2000"
-CGP fo Life-