A great lecture by Peter Lewin on capital theory. Lewin was a student of Ludwig Lachmann during his undergrad years and is very much influenced by Lachmann and it shows in this lecture. Lewin is the person that made me pick up my first Lachmann book. I discovered him a couple years ago by searching Austrian economists in Dallas, which is where I am from.
UPDATE: This is a more recent lecture by Lewin on capital, using the powerpoint linked in this post.