Recently (for fun), I built an HTML5 version of the current XBOX 360 dashboard. It received much praise as being good looking and highly interactive.
Unfortunately, due to the fact that Microsoft is releasing a new dashboard later this year named “Metro”, it is still kind of incomplete.
Things that do work are the Facebook integration and YouTube video watching. Mouse scrolling can be done in FF and navigation can be done with the arrow keys.
Requires a browser other than Internet Explorer and a window width equal or higher than 1024 px.
Metro dashboard is currently being worked on, it is much faster than the one here.
UPDATE :
Link to Metro Dashboard below
Metro