Halo 2: There's more to it than you think. Have you seen the "GameViewer?" And the Games RSS Feed?
Ya, ya, the graphics are great, game of the year, whee.
What's REALLY interesting is the ASP.NET application that runs Bungie.NET. You can link your Passport and XBox Live Gamer Tag and get statistical data on every game you (or anyone) has ever played. You can get details on clans, maps, friends, everything.
For example, here's a game (#650296) where Robert McLaws spanked me. Here's every game I played last night. Here's the details on Clan "Zen."
There's a depth to their data gathering that goes far beyond the game itself, and beyond anything XBox Live or any major massively multiplayer thing I've ever seen.
Additionally, are you ready for this? To the right here is a "GameViewer" with a view of each game, including perspectives on exactly where Robert kicked my ass in this specific game instance.
If that's not all? How about an RSS Feed of all my Halo 2 games?
Drink that in my friends. I wonder if there's some OLAP in there. I'd be fascinated to see the database schema.