According to Valve magnate Gabe Newell, Portal 2 has sold an impressive three million copies since it was released in April. While we'd have thrown a massive rager in their shoes, Valve's managing director, of course, delivered the news unconventionally, slipping it into his keynote today at the "Games for Change" festival.

Newell's speech at the conference—hosted yearly at NYU by the Games for Learning Institute—spanned a variety of societal topics, including why you may see Portal 2 in classrooms soon, Valve's successful Japan fundraiser in Team Fortress 2, and the impact of a growing worldwide marketplace for in-game content.

Regarding education, Newell indicated that he “doesn't see divide between making a game that can do well and be educational” and that Valve is “staring to work with schools to build curricula around Portal 2,” according to Stephen Totilo's liveblog of the speech on Kotaku.

Along with comments on the value of Portal's physics-based problem solving and light criticism of educational game designers, Newell showed off a video in which a class of 7th graders visited Valve's office for an educational day of game design instruction.

As should be expected from Newell, the keynote was a cascade of fascinating observations and questions. Unfortunately, a video of the presentation doesn't yet appear to be live on the festival's official site , but Totilo's liveblog offers a good recap in the meantime. Oh, and yes , Newell was of coursed asked when Half-Life 2: Episode 3 will be released, to which he allegedly responded, “If you know enough to ask the question, you know enough what the answer is.”

That obvious non-answer aside, how do you feel about the state of educational games? Could Portal 2 be manipulated such that it fits into a physics class? Let us know what you think in the comments.