Game ROMS are a way to run old console games (or new ones, but usually old ones) on your computer using an emulator. They have been pretty popular for a number of years, but technically they are not legal. (You know, like Napster) But now there is a service called StarROMs that offers game ROMs in a completely legal way, how cool! There current selection is kind of limited, but hopefully they will win over some of the other game companies and expand there offerings in the future.