The Halo 3 ending seems to have leaked to the internet.
A video (just a cellphone recorded vid?) is said to be available on YouTube detailing the end of one of the biggest games of 2007.
On digg you find words like:
HALO 3 ending – final cutscene! watch this, amazing! before it gets taken down!! Halo 3 – 1st mission ( start of the end ) leak!