Odd display corruption (get in here and explain, Maes)

I didn't alt-tab out of a 256 colour game, nor was I doing anything that would normally cause this, I simply went to a random site in chrome, and it decided to... do that. One of the most unusual gui corruptions I've ever seen, and I've even encountered windows running at 160x120... I'm not really asking "what's wrong with my pc", more like "what kind of driver failure would cause this, and how, and why".