I went to a Pixar animation exhibit this summer. They talked about how with Monster's Inc a large technical advancement was the ability to animate hair. Is animated hair just really small triangles, or do they do something more fancy?

@djevans Depends on which part of the graphics pipeline you're talking about. When it comes to rendering, yes, the hair very well may get diced up into little triangles. For simulation, there is almost surely a different representation, such as a polygonal curve, or maybe some kind of curve. For instance, there's been some nice work on modeling hair as "super helices".