Last year, I stopped using Khan Academy's CS platform because it only had a few very basic tutorials. Since then, they've added a huge course, covering topics like flow control (if-then statements), functions, and object oriented programming. You can see in my presentations below that I tried to teach these elements, but it was difficult because I couldn't build the interactive tutorials that make the Khan platform so powerful. Now we're using it to great success with our elementary Hackers!