The Halo franchise has been rife with early release issues thanks to a series of leaks and broken street dates throughout its history. Today it has been revealed Halo: Reach
has been leaked via Xbox Live as a copy of the game had been posted for reviewers with a price tag of 99,999 MS Points (obviously so no one could buy it).
Turns out a few clever people worked out how to pull it down for their own means, overcome some security within the game, and get to playing Bungie's last Halo effort. So if you're a Halo fan, you might want to start being wary of news and forum posts, as it's highly likely we'll be seeing spoiler material.
Microsoft are aware of the situation and are investigating how it happened, and ways in which to stop the leak going any further.