In Objectively Speaking, Rand is quoted as saying that she developed her theory of humor based on what an "acquaintance" suggested.
I'm wondering if this was Nathaniel Branden (and, of course, whether NB was edited out).
I'm reading this book (a collection of interviews) and it's fascinating.
In particular, I found Rand's discussion of libertarianism much more balanced than in the quotes you can find on the ARI's page.
In addition, Rand is sympathetic to restricting voting to those who have property.
She is also more supportive of state's rights than in other places:
I just finished this new book by Eastern Orthodox theologian and historian David Bentley Hart. Not really a response to the New Atheists, rather a review of the various claims against Christian history such as the Inquisition, Galileo, Hypatia, the library of Alexandria, Christianity and war, Christianity and science, etc. It's very well written.
Look like Prof. Gotthelf will be coming out with two new collections.
His CV lists:
1.  Concepts and Their Role in Knowledge: Ayn Rand's "New Approach to Epistemology" (with G. Salmieri, O. Ghate, and J.G. Lennox)
2.  Ayn Rand: A Companion to Her Works and Thought [20 chapters, 16 authors] (co-edited), Oxford: Blackwell
I've recently started reading some books in the Oneworld Thinkers series. These are introductory works on important thinkers. I've read Ed Feser on Locke and Harold Noonan on Hume. The length is about 200 pages each, so they are a bit more detailed than Oxford Past Masters (now part of the "Concise Introduction" series) or Wadsworth's series, but still manageable.
I would be interested in knowing what books or series that others have found useful in studying intellectual history.