This is not the full version but an early beta and if you want to start programming games (including multi-player) for the Zune media player you'll want to try this out. If you're still on Visual C# 2005 (Full or Express versions) you'll need to move to the 2008 editions but it works with the Express editions so it won't cost you a cent. It also works alongside the 2005 editions with the XNA Game Studio 2.0 so no uninstalling is needed.

You can download it from the Microsoft download page. At a modest 42MB it won't take too long.

• Link to So you want to be a Games Programmer