The Holy Logo
Stella is an Atari 2600 emula^H^H^H^H^HVirtual Machine, that allows you to run Atari 2600 software under OpenStep. The current version is only available for OpenStep/Mach 4.2 for Intel.
Once upon a time, I intended to port this to Mac OS X, but there's not much point now that a perfectly good Carbon port is available at the official Stella home page.