GeeXboX is a free embedded Linux distribution which aims at turning your computer into a so called HTPC (Home Theater PC) or Media Center. Being a standalone LiveCD-based distribution, it's a ready to boot operating system than works on any Pentium-class x86 computer or PowerPC Macintosh, implying no software requirement. You can even use it on a diskless computer, the whole system being loaded in RAM.

geexbox.org