Donald Clark's ongoing series of 50 blog posts in 50 days on (very loosely speaking) learning theorists. 

I've been tempted to bookmark the majority of Donald's posts in this series so far but it's hard to single any out and there are just so many to keep up with. Most of the posts provide wonderfully succinct explanations of a great range of theorist's ideas with relevance to learning or whose influence affected how teaching happens, as well as some great (and brief) critical analysis. Today's post on Maslow's ubiquitous hierarchy of needs is a good example that both explains and crushes the theory in one brief page. Many of the choices are surprising and not usually included in lists of learning theorists, including philosophers, religious leaders, biologists, psychologists, novelists and political thinkers.  Not all posts are of equal quality, but most posts on those outside the mainstream are at the very least thought provoking. An extremely eclectic range of ideas and people covered from Marx to Dewey, Jesus to Kolb, Locke to Gagne, Ignatius to Illich, and much much more, with good references and links to further reading. 

I'd highly recommend that anyone with an interest in education should start with the March 2012 archive and read them all. It's turning into a pretty complete introductory course in learning and related topics that every teacher and learning researcher should know about.