Some bonus thoughts in this comment: http://news.ycombinator.com/item?id=3921258 http://news.ycombinator.com/item?id=3921258 I like the idea of the code to aut

Some bonus thoughts in this comment: http://news.ycombinator.com/item?id=3921258 http://news.ycombinator.com/item?id=3921258 I like the idea of the code to authenticate students. I guess you'd have to watch out for selection effects in all of this too... an interesting challenge!