Xbox -> Hacking -> Software -> Emulators:

A software emulator is an application that allows you to run software designed for a different type of system, like older consoles. The emulator will convert the game code into something the Xbox can run, so you can play old games (referred to as Roms) on the Xbox.

Nes:

• FCE Ultra X
• MednafenX-NES
• NesterX
• XNES

Snes:

• xSnes9x
• Snes9x X
• ZsnexBox

Nintendo64:

• Surreal64
• Daedalus X
• PJ64-X

Playstation1:

• PCSXBox

ColecoVision/Adam:

• AdamX

Atari:

• Atari7800X
• AtariXLBox
• Stella
• Z26X

x86/DOS: (older pc games)

• Bochs
• DOSXBox
• XPCE-X

Sega Genesis/CD:

• DGen
• Gens_xport
• Xenesis

Arcade:

• FBA-X
• MAMEoX
• MAME-X
• MAMEdOX

Commodore64:

• Frodo-X
• Vice64X

Gameboy/GBA:

• Gnuboy
• Uvba
• XBoyAdvance
• eXtremeGB