XNA
Microsoft® XNA™ is composed of industry-leading software, services, resources, and communities focused on enabling game developers to be successful on Microsoft gaming platforms.

MSN Games
With more than 900 high-quality games, MSN Games offers fun and interactive gameplay through free casual single-player games, downloadable games, and premium multiplayer games!

Games on Windows Live Messenger
Millions of people in 30 different countries utilize the rich, interactive Windows LIVE Messenger platform to play more than two dozen single and dual-player games each month!

Microsoft Casual Games
Microsoft Casual Games develops, publishes, and distributes web-based and download games in every major casual game genre (puzzle, word, card and arcade).

Xbox LIVE
Xbox LIVE is the premiere online gaming and entertainment service. It’s a worldwide community of gamers connected through Xbox 360 and a high-speed Internet connection.