Hans-Lukas Teuber[1] was the head of the psychology department and my professor for the intro psychology class at MIT. He gave one two-hour evening lecture per week, which were delivered without notes. The lectures were riveting, they were given in MIT's largest lecture hall; it was standing room only to hear him speak--many students and faculty would attend even though not enrolled. I don't remember ever hearing a better live lecture than those that he gave (and I've heard many lectures--I spent more years at university than Belucci's character in Animal House).

He used the memory palace method to remember his lecture's organization.

[1] http://www.nasonline.org/publications/biographical-memoirs/m...