It would be cool if in the top right corner you had a suggestion box icon that would pop down a window in witch we can make a suggestion regarding the lesson on that page. I just had a lesson where I was to make an array for no reason as I did not need it to complete the lesson properly. (building an address book - more people) Also some of the error checking in a few of the lessons could be improved with live user feedback. It would be a cool thing I think for the guys who make this awesome site.
just my thoughts.