The Raspberry Pi may be designed as a cheap educational computer, but hardware-wise it has a lot in common with set top boxes. However, set top boxes are traditionally locked down and not easily modifiable by the user, the Pi is the opposite and is open to user experimentation. People have been building their own media centres for years and now the Pi offers a very cheap route into learning about this area. XBMC defines itself as a "software media player and entertainment hub" that is packed with features and offers a fairly friendly user experience which follows the ideas in the ten foot user interface. It has also been ported to work on the Pi. I've been experimenting with OpenELEC - a minimalistic Linux distribution that hosts XBMC and makes setting up this sort of environment on your Pi not as difficult as you might think.