MacMAME is part of the MAME project, a non-profit organization dedicated to preserving the history of arcade videogames via emulation. MacMAME achieves this by running the original program code found in the arcade games. As such, it is much more than a reproduction, it is essentially that same game running via an emulated layer inside your Mac.

Requirements:
OS X 10.2-10.5
ROMs are required by MacMAME in order to actually be able to play the games. They contain the program and graphics data for each game.
PPC