Basilisk II is an Open Source 68k Macintosh emulator. That is, it allows you to run 68k MacOS software.

Release notes:

Replace the basiliskII file in any other version with the one in this zip. Be sure not to use any TV out options in the config file, these are not supported. Also there is no MMU hack.

What’s New:
Mouse Acceleration (increases as you move, decreases as you don’t, also wraps around screen like in Pacman)
Start is mapped to enter.