(aka Xbox Meda Player, which is the pre-1.0 release of XBMC)
http://www.xboxmediacenter.de/
XboxMediaCenter (XBMC) is a multimedia player jukebox for Microsoft Xbox game console, it is capable of playing back almost all known video, audio and picture formats from the Xbox harddrive, Xbox DVD-ROM, from a local network or even from Internet.
One page links to XboxMediaCenter: