XBMC is the best open source (GPL), free entertainment hub you can find on internet. XBMC is really easy to install (for Linux users, especially in Ubuntu) and its features are very intuitive and simple to configure. Moreover the graphics themes are very attractive and it is able to manage many multimedia formats, "playlists, audio visualizations, slideshow and weather forecast functions". It is also possible to add many interesting third-party plugins that you can find through a simple google query (XBMC plugin). Last, but not least, XBMC is a multiplatform software, in fact the download page contains four different versions for Windows, XBox, Linux and MAC OSX. When we compared XBMC to the Windows Media Center we did not notice any loss in this open-source media center and, honestly, we were positively impressed by all the XBMC featured we tested. Recommended!