MESS

MESS (short for Multi Emulator Super System) is a suite of emulators for a variety of computers and game consoles. It is a sister project to MAME, which focuses on emulating Arcade Games and shares large portions of MAME's source code as well as the same distribution licence (you're not allowed to sell it or use the source code in anything which will be sold).

The list of emulated systems is too extensive to include here, but as of version 0.148 it covers 668 unique systems, with the emulation in various stages of development ranging from barely started (more recent or obscure systems) to virtually perfect (older or well-known systems).

Like MAME, MESS focuses on accuracy rather than speed with the overall goal of preserving computing history. Where the two projects have emulated hardware in common, it'll be implemented in MAME first, then filter through to MESS the next time the developers synchronise the shared branches of the source tree.

You can download MESS from the project's official website: http://www.mess.org/