The Design Of Computer Programs on Udacity by Peter Norvig is pretty awesome. As someone who's only been seriously programming for a year or two , each problem set went like this :

Write the code here to do X :

I write a messy 4 liner after lots of thinking.

Professor Norvig comes along and does it in a simple functional one liner.

Mind blown.

He teaches good functional style program design one epiphany at a time.