I had one of those this-is-what-makes-it-all-worthwhile events this morning. Yesterday, I did one of my "classroom visits" (a.k.a., teacher observation) and during part of the class a student was invited to the overhead projector to demonstrate how to solve a problem to the rest of the class (third grade). But as he tried to explain how to do the problem, he got all confused and stuck and couldn't work his way through it.