Final Burn Legends is an Arcade emulator for the original Xbox. It plays and supports over 2,700 games. In this video (via The Games Shed) they give you a demo of the games packed in the great Arcade emulator. Keep in mind, there are about 100 + Emulators for the Original Xbox which vary from Atari, Super Nintendo (SNES) to Nintendo 64 (N64) and PlayStation (PSX) so be sure to give those a try as well.
To be able to install emulators on the original Xbox you must soft-mod it. Afterwards, you can start installing ROMs and emulators via FTP, we provide all the tutorials in the links below.
Final Burn Legends
Final Burn Legends is a port of Final Burn Alpha 2.99.07 to the original Xbox. It also includes parts of FBA-XXX Pro 1.29. Support for over 2700 games. Some games are not playable anywhere else on the original Xbox. New in this rel: Optimized each original Xbox binary compiled per instruction from 'freakdave' over at emuxtras.net. Added 2 wide icons for those of you who use them.
* mini rom pack download for Final Burns Legends v.1.12
How To: Install ROMs and Emulators on Original Xbox via FTP + Download Links