It's difficult to say what defines a game. Obviously, there are lots of different factors, and at GDC this morning there was a conference with three developers who were discussing just that.

What they talk about is actually very, very deep, considering things like the psychology behind gaming, what makes games fun, and what people want out of games these days. Headed by the main developers for flOw and Everyday Shooter, and one other indie developer, this is one of the few things about the gaming industry that makes people who work in it proud to do what they do.

via Destructoid