Atari has released the source code of over 15 games developed and sold for the Atari 7800.
Games released include Dig Dug or Centipede or Robotron, although notably you’ll need a 7800 emulator to run any of them.
According to Programmerfish, Atari said the purpose of the release is to give potential developers insight into the Atari’s gaming platform so they may possibly build upon the 7800 series. Why people would want to build upon the 7800 in 2009 I don’t know, but I still like the sound of it.
Downloads available at Programmerfish here.