Wikipedia
MythTV
MythTV is a free and open source home entertainment application with a simplified " 10-foot user interface" design for the living-room TV, and turns a computer with the necessary hardware into a network streaming digital video recorder, a digital multimedia home entertainment system, or home theater personal computer. It can be considered a free and open source alternative to TiVo or Windows Media Center. It runs on various operating systems, primarily Linux, Mac OS X and FreeBSD.