Personally, I'm partial to: http://conceptviz.github.io/ http://conceptviz.github.io/ edit: this is more about visual explanations, but I think a lot of ideas

Personally, I'm partial to: http://conceptviz.github.io/ http://conceptviz.github.io/ edit: this is more about visual explanations, but I think a lot of ideas are transferable and go hand in hand