You can play some original Xbox games on your Xbox 360 console if you have an official Xbox 360 Hard Drive.
Notes
The following game list is final as of November 2007. No additional original Xbox games will be added to this list.
Note This is a list of titles that have been certified for compatibility with Xbox 360. The list is provided for informational purposes only and is subject to change without notice. To ensure the highest quality gaming experience, in the event an unforeseen technical issue is discovered after certification is completed, Microsoft reserves the right to remove any game name from this list.
Footnotes
[1] The North American versions of these games are the only ones supported on the Xbox 360 console.
[2] The Japanese version of this game is not supported on the Xbox 360 console.