Microsoft has recently updated their free XNA Game Studio development environment that allows anybody to create games for Xbox 360 and distribute to the millions of Xbox users via Xbox Live.
Developers need to be proficient in C# Visual Studio but the process thereof is a relatively straight forward one of development, peer review and release.
Making the Xbox so open in this manner may well give Microsoft a lead in the game based learning field if the popular XBox 360 console can be used to deliver bespoke games (even serious ones

) as well as off the shelf ones.

More info at:
http://creators.xna.com/en-GB/