Pac-Man has been extensively hacked.
(Note: include some utilites here for Pac-Man)
There are about a dozen ROM hacks for Pacman. Here is a list of all known Pac-Man ROM hacks:
Until Pac-Man was released in the arcades, arcade video games in North America were primarily "space shooters," or video games where people controlled spaceships in space that had to shoot something (asteroids, aliens, etc). Since then, video arcade games have diversified (and even became educational.)
(Note: include some links here)