[Upate: 9:20 AM:] Works fine now. Microsoft has fixed the issue. Ignore story below.
Microsoft's Xbox Game Room is now live, but is plagued with problems. The online place to "relive the glory days of arcade games" is available for download, but don't expect it to, you know, work right away or anything. Interested gamers are able to download Game Room, but when you try to load either of the two game packs themselves, the system hangs on the loading screen.
Microsoft are looking into it, so hopefully soon you'll be able to play the 30 classic arcade games the system offers.
Here's Major Nelson's tweet:
One more time: Game Room is available, but there is a problem loading some of the games. This is being investigated.
Game Room offers a bunch of achievements, as well as allowing you to customize your own arcade, and buy arcade titles; either for the full price or for a fee of $.50 --- just like a real arcade... but twice as pricey as the old quarter-a-throw.