Spread the Knowledge
I personally think there isn't a moment that a child should not be learning. They have the ability to absorb information at rates that adults dream of. This doesn't mean that learning should be devoid of fun. You can learn while playing basketball, a board game, during just about anything (wink, LOL).
I've just played learning games with my two nieces and my nephew. Most of the conversation was dominated by the eight and ten year old.
The gauntlet of subjects included a very interesting discussion of religion (to which they grilled me), the Civil War, the American Revolution, tectonic plates, etc.
More than anything I find that this learning process is mutually beneficial. I have learned things from children that I haven't from adults. I've also been refreshed on topics that I haven't thought about in years.
My greatest goal is to make sure that I can keep the children open-minded, as I try to be myself. They don't need their minds cluttered with misconceptions from adults. I'd prefer if they are close-minded (as they age), perish the thought, that it results from their own experiences and not those of parents, family members, television, or friends.