Well, depending on the game that you want you'll need an emulator.
Such as a Super Nintendo, regular Nintendo, or Sega which is soon to
come, and if you really want it just mail me.
NES Emulators
SNES Emulators
Super Special! I now have emulators for Macs!
Macintosh
Emulators For Macintosh Users
I had a few complaints from mac owners who wanted some emulators so I got some, I hope they are happy.
But you are on your for roms, I'm sorry to say I haven't located any of them for Macs.
NES for macs only
SNES emulator for macs only