I wonder if perhaps kids find the assigned work so dreadful because the manner of assignment assumes it will be. "Why should I read this?," asks the kid. "Because it is assigned," comes the answer. At which point, perhaps the child thinks, "Oh, you don't care about this, so why should I?," and the battle lines are drawn.

In other words, maybe the issue isn't whether or not something is assigned. Maybe the issue is whether or not the teacher cares about - and is excited about - the material. If the teacher thinks it is fun, maybe being assigned it is not such a heavy burden to bear.