Boycott/MacOS is a Nintendo Gameboy emulator for the Macintosh.
While Boycott features reasonably good compatibility, it does not have a speed limiting mechanism, meaning that is runs much too fast on modern Macs. It is probably only useful to people running on 150MHz or slower machines. Unfortunately, due to a bad CD-R, I no longer have a copy of the Macintosh-specific source code. I do not, at this time, have the motivation to restart this port, as Virtual Gameboy for the Macintosh supports Colour, Sound, and Super Gameboy - all things which as yet Boycott does not have.
 
Boycott was initially developed by Julien Frelat for MS-DOS and Unix. The source code for Boycott is not available to the public. Julien has also started developing a PC emulator - I wish him luck with that.