Mame

"Multiple Arcade Machine Emulator"

Been around for quite some time, although recently found the emulator and a few ROM's on an old hard drive.

A good case for nostalgia without the smell of pizza and begging your parents for quarters.

The Emulator

Mac

Windows

ROMS

One of many sites hosting an abundance of files for download.

http://www.rom-world.com/

1941

Double Dragon

Galaga

Knights of the Round

Metal Slug 3

Mortal Kombat

Rampage - World Tour

Street Fighter II - The World Warrior

Sunset Riders

Teenage Mutant Ninja Turtles - Turtles in Time

Doubt all of these links are working, although just a few examples of the games accessible, there are alternate downloads available on the mentioned and other sites.